Dual frequency matching circuit for inductively coupled plasma (ICP) loads

Abstract

A matching circuit for generating electricity in plasma processing devices or other applications is disclosed. The matching circuit is provided in a single physical housing and configured to provide impedance matching at multiple different frequencies. For example, in a dual-frequency implementation, first and second RF generators can provide electromagnetic energy to the matching circuit, which includes first and second circuit sections, at their respective first and second frequencies in either continuous or pulsed mode. The first circuit section may include one or more first tuning elements configured to receive RF power at a first frequency and provide impedance matching for a first ICP load (e.g., a primary sensing element). The second circuit section may include one or more second tuning elements configured to receive RF power at a second, different frequency and provide impedance matching for a second ICP load (e.g., an auxiliary sensing element).

Description

[Technical Field]

[0001] This disclosure generally relates to matching circuits that provide integrated matching for multiple frequencies. More specifically, dual-frequency matching circuits can be incorporated into a power generation system or used in a plasma processing apparatus that uses a plasma source to process the substrate. [Previous Technology]

[0002] RF plasma is used in the fabrication of integrated circuits, micromechanical devices, flat panel displays, and other devices. RF plasma sources used in modern plasma etching applications require high plasma uniformity and multiple plasma controls, including independent control of plasma profile, plasma density, and ion energy. RF plasma sources must typically be able to maintain stable plasma in various process gases and under diverse conditions (such as gas flow rate, gas pressure, etc.). Furthermore, RF plasma sources should ideally have minimal environmental impact by reducing energy requirements and electromagnetic radiation.

[0003] Various known plasma sources exist to meet these stringent plasma process requirements. Multi-frequency capacitively coupled plasma (CCP) sources have been used to independently control ion energy and plasma density. Inductively coupled plasma (ICP) sources, combined with RF bias, are also used, for example, to provide independent control of ion energy and plasma density. Using standard 13.56 MHz and lower frequency RF power generators, ICP sources can easily generate high-density plasma. In fact, it is well known that using multi-coil ICP sources can provide good plasma control and high plasma density.

[0004] In known ICP source configurations, RF power is provided at first and second different frequencies to excite first and second different coils (e.g., source coil and center coil) in the ICP source. However, existing systems include two separate RF delivery systems for the source power and center power, and lack pulse functionality. Such an arrangement increases cost, inhibits maintainability, and limits potential applications in plasma processing and other suitable systems. [Summary of the Invention]

[0005] Aspects and advantages of the invention will be set forth in part in the description which follows, or may be apparent from the description or may be learned by practice of the invention.

[0006] An exemplary aspect of this disclosure relates to a dual-frequency matching circuit, including first and second input ports, a matching circuit, and first and second output ports. The first input port is configured to receive RF power at a first frequency, and the second input port is configured to receive RF power at a second frequency, different from the first frequency. The matching circuit is provided in a single physical housing and includes respective first and second circuit portions. The first circuit portion includes one or more first tuning elements configured to receive RF power at the first input port and provide impedance matching for a first load. The second circuit portion includes one or more second tuning elements configured to receive RF power at the second input port and provide impedance matching for a second load. The first output port is coupled to the first circuit portion of the matching circuit and configured to provide a first output signal to the first load at the first frequency. The second output port is coupled to the second circuit portion of the matching circuit and configured to provide a second output signal to the second load at the second frequency.

[0007] Another exemplary aspect of this disclosure relates to a power generation system for an inductively coupled plasma (ICP) load. The power generation system includes first and second RF generators, matching circuitry, and a single physical housing. The first RF generator is configured to provide electromagnetic energy at a first frequency in either continuous or pulsed mode. The second RF generator is configured to provide electromagnetic energy at a second frequency in either continuous or pulsed mode, wherein the second frequency is different from the first frequency. The matching circuitry includes first and second respective circuit portions. The first circuit portion includes one or more first tuning elements configured to receive electromagnetic energy at the first frequency and provide impedance matching for a first ICP load. The second circuit portion includes one or more second tuning elements configured to receive electromagnetic energy at the second frequency and provide impedance matching for a second ICP load. A single physical housing houses the first and second circuit portions.

[0008] Another exemplary aspect of this disclosure relates to a plasma processing apparatus, including a processing chamber, a substrate support, first and second sensing elements, and a matching circuit. The processing chamber has an internal space operable to receive process gases. The substrate support is provided within the internal space of the processing chamber and operable to hold a substrate. The first and second sensing elements are located at different positions relative to the processing chamber. The matching circuit is provided in a single physical housing and includes a first circuit portion and a second circuit portion. The first circuit portion of one or more first tuning elements is configured to receive RF power at a first frequency and provide impedance matching for a first ICP load including the first sensing element. The second circuit portion of one or more second tuning elements is configured to receive RF power at a second frequency and provide impedance matching for a second ICP load including the second sensing element, wherein the second frequency is different from the first frequency.

[0009] These exemplary embodiments of the present disclosure may be varied and modified.

[0010] These and other features, aspects, and advantages of the invention will be better understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

Implementation Method

[0017] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope or spirit of the invention. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover such modifications and variations within the scope of the appended claims and their equivalents.

[0018] Exemplary aspects of this disclosure relate to circuits, systems, apparatus, and related techniques for implementing multi-frequency matching for circuit load elements (e.g., inductively coupled plasma (ICP) loads). Matching circuits can be designed to provide at least first and second respective circuit portions for providing impedance matching for radio frequency (RF) power at respective first and second different frequencies. However, when matching is used at first and second different RF power levels, conventional solutions involve two separate RF delivery systems. The technology of this subject provides an integrated dual-frequency matching design by providing impedance matching elements for multiple frequencies (such as first and second different frequencies) within a single physical housing, which also offers the advantages of reduced cost and improved maintainability.

[0019] More specifically, an example aspect of the disclosed technology may relate to a matching circuit comprising multiple input ports, provided in a single physical housing housing all components of the matching circuit, and multiple output ports. Each input port may be configured to receive RF power at a different frequency. The matching circuit may include multiple circuit sections corresponding to the number of different input ports receiving RF power. Each circuit section may include one or more tuning elements configured to receive RF power at its respective input port and provide impedance matching for a corresponding load (e.g., an ICP load). Each output port may be coupled to its respective circuit section of the matching circuit and configured to provide a corresponding output signal to its corresponding load at one of the selected different frequencies.

[0020] For example, in a dual-band implementation, the dual-band matching circuit may include first and second input ports, a matching circuit including first and second circuit portions, and first and second output ports. The first input port may be configured to receive RF power at a first frequency, while the second input port may be configured to receive RF power at a second frequency different from the first frequency. The matching circuit may include first and second respective circuit portions, which are housed together in a single physical housing. The first circuit portion may include one or more first tuning elements configured to receive RF power at the first input port and provide impedance matching for a first load (e.g., an ICP load). The second circuit portion may include one or more second tuning elements configured to receive RF power at the second input port and provide impedance matching for a second load. The first output port may be coupled to the first circuit portion of the matching circuit and configured to provide a first output signal to the first load at the first frequency. The second output port may be coupled to the second circuit portion of the matching circuit and configured to provide a second output signal to the second load at the second frequency.

[0021] Although some examples of designs and topologies, such as the ones above, are presented in the context of dual-frequency matching designs, these principles can be extended to tri-frequency or other multi-frequency matching implementations.

[0022] According to another aspect of the disclosed technology, the matching circuit can be designed for a variety of different load types and corresponding applications. One specific application relates to a matching circuit for inductively coupled plasma (ICP) loads. For example, an ICP load can correspond to first and second sensing elements (e.g., source coil and center coil) in a plasma processing apparatus. Although some examples are presented in the context of ICP loads, the circuit load element can also correspond to capacitively coupled plasma (CCP) loads, bias applications, and / or other suitable applications.

[0023] According to another aspect of the disclosed technology, a plurality of RF generators can be provided to generate RF power at a plurality of different frequencies. For example, a first RF generator can be provided to generate RF power at a first frequency, which is directed to a first input port and a first circuit portion of a matching circuit. A second RF generator can be provided to generate RF power at a second frequency, which is directed to a second input port and a second circuit portion of a matching circuit. In some implementations, RF power at the first frequency is provided at a power level and frequency greater than that at the second frequency. As an example, RF power at the first frequency can be provided at a power level in the range of about 1 kilowatt (kW) to about 5 kW (e.g., about 2 kW) and a frequency in the range of about 12.75 MHz to about 14.25 MHz (e.g., about 13.56 MHz), and RF power at the second frequency can be provided at a power level in the range of about 500 watts to about 3 kW (e.g., about 1 kW) and a frequency in the range of about 1.75 MHz to about 2.15 MHz (e.g., about 2 MHz).

[0024] In some implementations, each RF generator is configured to provide power in continuous and / or pulsed modes. By including RF generators capable of selective operation in continuous and pulsed modes, the disclosed power generation system and associated matching circuitry can provide enhanced capabilities for a wider range of applications. For example, in plasma processing applications, new process applications integrating nitriding and / or nitriding and annealing require the hardware capabilities of pulsed RF plasma.

[0025] According to another aspect of the disclosed technology, the matching circuitry is configured to be housed together in a single, single physical housing. This integrated approach facilitates overall system design, making it easier to maintain and more compact, particularly compared to conventional implementations where each RF source requires separate and distinct matching circuitry. In some examples, one or more metal partitions may be provided within a single physical housing housing all components of the matching circuitry. The number of metal partitions required may depend on whether the matching circuitry is provided for dual-band, tri-band, or other multi-band approaches. Generally, the number of metal partitions is chosen to ensure positioning and physical separation between each circuit section. In a dual-band implementation, the metal partitions may be positioned between the first and second circuit sections, and physically space the first and second circuit sections.

[0026] According to another aspect of the disclosed technology, each circuit portion in the matching circuit may include a corresponding bypass filter element configured to filter out residual power at frequencies other than the frequency used for a given circuit portion. Referring again to an example of a dual-frequency matching circuit, the matching circuit may include a first bypass filter element and a second bypass filter element. The first bypass filter element may be provided between, for example, a first input port and one or more first tuning elements, and may be configured to filter out residual power leaking to the first circuit portion at a second frequency. The second bypass filter element may be provided between, for example, a second input port and one or more second tuning elements, and may be configured to filter out residual power leaking to the second circuit portion at a first frequency. The first and second bypass filter elements may correspond to one or more passive circuit elements, such as, but not limited to, capacitors and / or inductors. In a particular implementation, for example, the first bypass filter element may be an inductor, and the second bypass filter element may be a capacitor.

[0027] According to another aspect of the disclosed technology, one or more tuning elements in each circuit section of the matching circuit can take various specific configurations. In some implementations, each group of multiple tuning elements (e.g., one or more first tuning elements in a first circuit section and one or more second tuning elements in a second circuit section) can respectively include parallel capacitors and series capacitors. In some implementations, each group of multiple tuning elements (e.g., one or more first tuning elements in a first circuit section and one or more second tuning elements in a second circuit section) can additionally include respective parallel inductors and series inductors.

[0028] More specifically, in some embodiments, each parallel capacitor may be positioned between a bypass filter element and a series capacitor in its corresponding circuit section. For example, in a dual-frequency embodiment, the parallel capacitor in the first circuit section may be positioned between a first bypass filter element and a series capacitor in the first circuit section. Similarly, the parallel capacitor in the second circuit section may be positioned between a second bypass filter element and a series capacitor in the second circuit section.

[0029] More specifically, in other embodiments, each parallel capacitor may be positioned between the series capacitor in its corresponding circuit section and the output port. For example, in a dual-frequency embodiment, the parallel capacitor in the first circuit section may be positioned between the series capacitor in the first circuit section and the first output port. Similarly, the parallel capacitor in the second circuit section may be positioned between the series capacitor in the second circuit section and the second output port.

[0030] According to another aspect of the disclosed technology, the matching circuit may include one or more signal monitors configured to monitor various signal levels of the RF power provided by the matching circuit.

[0031] In some embodiments, for example, each circuit portion of the matching circuit may include a phase-amplitude detector coupled to a corresponding input port, the phase-amplitude detector being configured to measure the phase angle between voltage, current, and / or the voltage and current of the RF power supplied to the input port. In a dual-frequency embodiment, the matching circuit may include first and second phase-amplitude detectors. The first phase-amplitude detector may be coupled between the first input port and the first circuit portion and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power supplied to the first input port at a first frequency. The second phase-amplitude detector may be coupled between the second input port and the second circuit portion and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power supplied to the second input port at a second frequency.

[0032] In other embodiments, for example, each circuit portion of the matching circuit may include a voltage-current (VI) probe coupled to a corresponding output port, the VI probe being configured to provide measurements of the voltage and current supplied to the output port. In a dual-frequency embodiment, the matching circuit may include first and second VI probes. The first VI probe may be coupled between the first circuit portion and the first output port and may be configured to measure the RF voltage and RF current of the first output signal. The second VI probe may be coupled between the second circuit portion and the second output port and may be configured to measure the RF voltage and RF current of the second output signal.

[0033] Another embodiment of the disclosed technology corresponds to a power generation system for, for example, an inductively coupled plasma (ICP) load. Such a power generation system may include multiple RF generators, each configured to provide electromagnetic energy at a different frequency. For example, in a dual-frequency embodiment, the power generation system may include a first RF generator configured to provide electromagnetic energy at a first frequency and a second RF generator configured to provide electromagnetic energy at a second frequency different from the first frequency. In some examples, each RF generator may be configured to operate in a continuous mode and / or a pulsed mode. For example, a mode selection controller may be coupled to each RF generator and configured to provide electronic signal control for switching between continuous and pulsed modes depending on the load application.

[0034] Still referring to the example implementation of the disclosed technology, the power generation system may further include a matching circuit comprising multiple circuit sections, one for each RF generator provided in the power generation system. Each of the multiple circuit sections may include one or more tuning elements configured to receive RF power at a respective frequency level and provide impedance matching for a corresponding load (e.g., an ICP load). For example, in a dual-band implementation, the matching circuit may include first and second circuit sections. The first circuit section may include one or more first tuning elements configured to receive electromagnetic energy at a first frequency and provide impedance matching for a first ICP load. The second circuit section may include one or more second tuning elements configured to receive electromagnetic energy at a second frequency and provide impedance matching for a second ICP load. The matching circuit may further include a single physical housing housing all circuit sections (e.g., the first and second circuit sections). Optionally, metal partitions may be included to physically space the circuit sections within a single physical structure.

[0035] Another embodiment of the disclosed technology corresponds to a plasma processing apparatus. The plasma processing apparatus may include a processing chamber having an internal space operable to receive process gases, and a substrate support located inside the processing chamber operable to hold a substrate. The plasma processing apparatus may include first and second ICP loads. For example, the first and second ICP loads may each include first and second sensing elements positioned at different locations relative to the processing chamber.

[0036] The first sensing element may correspond to, for example, a primary coil or source coil in an ICP application, while the second conductive element may correspond to, for example, a secondary coil or center coil in an ICP application. Matching circuitry may be provided in a single physical housing and configured to provide tuning power to the first and second sensing elements. For example, a first circuit portion of one or more first tuning elements may be configured to receive RF power at a first frequency and provide impedance matching for a first ICP load including the first sensing element. A second circuit portion of one or more second tuning elements may be configured to receive RF power at a second frequency and provide impedance matching for a second ICP load including the second sensing element, wherein the second frequency is different from the first frequency.

[0037] Still referring to an exemplary embodiment of the plasma processing apparatus, the matching circuit may be designed to provide integrated tuning power to multiple sensing elements, such as primary and secondary coils. The primary coil may be spaced from the processing chamber by a Faraday shield. The secondary coil may be spaced from the primary coil by an electromagnetic shield to prevent crosstalk between the coils. In a particular embodiment, different RF frequencies are selected for use on the first and second sensing elements. These frequencies are selected to reduce crosstalk between the first and second sensing elements in the plasma and to provide enhanced independent control of the sensing elements.

[0038] The systems and methods according to the exemplary aspects of this disclosure can provide several technical effects and benefits, including but not limited to improvements in power generation systems and plasma processing apparatuses. For example, the exemplary aspects of this disclosure can provide an enhanced range of RF power applications, including ICP loads, CCP loads, bias applications, and others. Furthermore, since the RF generator and corresponding matching circuitry can be designed to operate selectively in continuous and pulsed modes, utilization in plasma processing applications, including nitriding and / or integrated nitriding and annealing, is possible. Moreover, integrating matching circuitry tuned to multiple different frequencies in a single, unified structure can reduce the overall system cost, make the design more compact, and facilitate easier maintenance.

[0039] FIG1 depicts a block diagram of a power generation system according to an exemplary embodiment of the present disclosure. More specifically, the power generation system 100 is designed to serve load elements operating at multiple different frequencies. Although a dual-frequency implementation is illustrated in the specific example of FIG1, the elements and concepts can be extended to cover tri-frequency or other multi-frequency configurations. The power generation system 100 may include a first RF generator 102 configured to generate a first RF power 103 that provides electromagnetic energy at a first frequency. The power generation system 100 may also include a second RF generator 104 configured to generate a second RF power 105 that provides electromagnetic energy at a second frequency different from the first frequency.

[0040] In some examples, the first frequency and / or power level of the first RF power 103 is greater than the second frequency and / or power level of the second RF power 105. For example, in some specific implementations, as an example, the first RF power 103 at the first frequency may be provided at a power level in the range of about 1 kW to about 5 kW (e.g., about 2 kW) and at a frequency in the range of about 12.75 MHz to about 14.25 MHz (e.g., about 13.56 MHz), and the second RF power 105 at the second frequency may be provided at a power level in the range of about 500 watts to about 3 kW (e.g., about 1 kW) and at a frequency in the range of about 1.75 MHz to about 2.15 MHz (e.g., 2 MHz).

[0041] In some examples, the first RF generator 102 and / or the second RF generator 104 may be configured to operate in continuous mode and / or pulse mode. For example, a mode selection controller may be coupled to each of the first RF generator 102 and / or the second RF generator 104 and may be configured to provide electronic signal control for switching between continuous mode and pulse mode according to the load application.

[0042] Still referring to FIG. 1, a first RF power 103 and a second RF power 105 can be provided to a dual-frequency matching circuit 106, which includes multiple circuit sections, one for each RF generator provided in the power generation system 100. Because FIG. 1 depicts a dual-frequency implementation, the matching circuit 106 may include first and second circuit sections, each including one or more tuning elements configured to receive RF power at their respective frequency levels and provide impedance matching for corresponding loads (e.g., first ICP load 108 and second ICP load 110). For example, the matching circuit 106 may include a first circuit section containing one or more first tuning elements configured to receive the first RF power 103 and provide impedance matching for the first ICP load 108. The matching circuit 106 may further include a second circuit section containing one or more second tuning elements configured to receive the second RF power 105 and provide impedance matching for the second ICP load 110. Therefore, the matching circuit 106 can generate a first output signal 107 provided to the first ICP load 108 and a second output signal 109 provided to the second ICP load 110. Other embodiments of the matching circuit 106 are described and illustrated with reference to Figures 2-4.

[0043] In some embodiments, such as those relating to a plasma processing apparatus, the first ICP load 108 may include a primary sensing element (e.g., a source coil), while the second ICP load 110 may include an auxiliary sensing element (e.g., a center coil), as described, for example, with reference to FIG. 5. Although FIG. 1 depicts the first ICP load 108 and the second ICP load 110, it should be understood that the matching circuit 106 can be designed for a variety of different load types and corresponding applications. Although some examples are presented in the context of ICP loads, the circuit load element may also correspond to capacitively coupled plasma (CCP) loads, bias applications, and / or other suitable applications.

[0044] FIG2 depicts a first exemplary dual-frequency matching circuit 106a according to an exemplary embodiment of the present disclosure. The dual-frequency matching circuit 106a includes a first input port 120, a matching circuit 121, a first circuit portion 122, a first bypass filter element 124, a physical housing 125, a first parallel capacitor 126, a first parallel inductor 128, a first series capacitor 130, a first series inductor 132, a first phase amplitude detector 134, a first VI probe 136, a first output port 138, a second input port 140, a second circuit portion 142, a second bypass filter element 144, a second series capacitor 146, a second series inductor 148, a second parallel capacitor 150, a second phase amplitude detector 154, a second VI probe 156, a second output port 158, and a distance 160.

[0045] The first input port 120 can be configured to receive RF power at a first frequency (e.g., the first RF power 103 of FIG. 1), while the second input port 140 can be configured to receive RF power at a second frequency different from the first frequency (e.g., the second RF power 105 of FIG. 1). The dual-frequency matching circuit 106a may include a matching circuit 121, which includes a first circuit portion 122 and a second circuit portion 142 housed together in a single physical housing 125. The first circuit portion 122 may include one or more first tuning elements (e.g., a first parallel capacitor 126, a first parallel inductor 128, a first series capacitor 130, and a first series inductor 132) configured to receive the RF power at the first input port 120 and provide impedance matching for a first load (e.g., the first ICP load 108 of FIG. 1). The second circuit section 142 may include one or more second tuning elements (e.g., a second series capacitor 146, a second series inductor 148, and a second parallel capacitor 150) configured to receive RF power from the second input port 140 and provide impedance matching for a second load (e.g., the second ICP load 110 of FIG. 1). The first output port 138 may be coupled to the first circuit section 122 of the matching circuit 121 and configured to provide a first output signal to the first load (e.g., the first ICP load 108 of FIG. 1) at a first frequency. The second output port 158 ​​may be coupled to the second circuit section 142 of the matching circuit 121 and configured to provide a second output signal to the second load (e.g., the second ICP load 110 of FIG. 1) at a second frequency. In some implementations, the first output port 138 and the second output port 158 ​​may be spaced apart from each other by a distance 160, selectable within a range of about 1 inch to about 35 inches.

[0046] Still referring to FIG. 2, the components of the matching circuit 106a are configured to be housed together in a single, single physical housing 125. For example, the physical housing 125 may house a first phase amplitude detector 134, a second phase amplitude detector 154, a matching circuit 121 including a first circuit portion 122 and a second circuit portion 142, a first VI probe 136, and a second VI probe 156. In some examples, one or more metal partitions 127 may be provided within the single physical housing 125 to ensure positioning and physical separation between each circuit portion. In the dual-frequency implementation of FIG. 2, the metal partition 127 may be positioned between the first circuit portion 122 and the second circuit portion 142, and physically space the first circuit portion 122 and the second circuit portion 142.

[0047] According to another aspect of the disclosed technology, the first circuit portion 122 and the second circuit portion 142 in the matching circuit 121 may include corresponding bypass filter elements (e.g., first bypass filter element 124 and second bypass filter element 144) configured to filter out residual power at frequencies other than those used for a given circuit portion. The first bypass filter element 124 may be provided between, for example, the first input port 120 and one or more first tuning elements, and may be configured to filter out residual power leaking to the first circuit portion 122 at a second frequency (e.g., about 2 MHz). The second bypass filter element 144 may be provided between, for example, the second input port 140 and one or more second tuning elements, and may be configured to filter out residual power leaking to the second circuit portion 142 at a first frequency (e.g., about 13.56 MHz). The first bypass filter element 124 and the second bypass filter element 144 may each correspond to one or more passive circuit elements, such as, but not limited to, capacitors and / or inductors. In one specific implementation, for example, the first bypass filter element 124 may be an inductor, while the second bypass filter element 144 may be a capacitor.

[0048] Still referring to FIG. 2, one or more tuning elements in each of the first circuit section 122 and the second circuit section 142 of the matching circuit 106a can take various specific configurations. For example, one or more first tuning elements in the first circuit section 122 may include a first parallel capacitor 126 and a first series capacitor 130, one or both of which may correspond to a variable capacitor. In some implementations, one or more first tuning elements in the first circuit section 122 may include a first parallel inductor 128 and a first series inductor 132. The first parallel capacitor 126 and the first parallel inductor 128 are connected in series and positioned between the first bypass filter element 124 and the first series capacitor 130 in the first circuit section 122. The first series capacitor 130 is connected in series with the first series inductor 132, both positioned between the first parallel capacitor 126 and the first output port 138. Example ranges of component values ​​in the first circuit section 122 may include: an inductance value of the first bypass filter element 124 between about 1 μH and about 5 μH, a capacitance value of the first parallel capacitor 126 between about 20 pF and about 2000 pF, an inductance value of the first parallel inductor 128 between about 0 μH and about 0.5 μH, a capacitance value of the first series capacitor 130 between about 5 pF and about 500 pF, and an inductance value of the first series inductor 132 between about 0 μH and about 1 μH.

[0049] One or more second tuning elements in the second circuit section 142 may include a second parallel capacitor 150 and a second series capacitor 146, one or both of which may correspond to a variable capacitor. In some embodiments, one or more second tuning elements in the second circuit section 142 may include a second series inductor 148. The second series capacitor 146 is connected in series with the second series inductor 148, both positioned between the second bypass filter element 144 and the second parallel capacitor 150. Example ranges of values ​​for the elements in the second circuit section 142 may include: a capacitance value of the second bypass filter element 144 between about 0 pF and about 500 pF, a capacitance value of the second series capacitor 146 between about 50 pF and about 10 nF, and a capacitance value of the second parallel capacitor 150 between about 50 pF and about 10 nF.

[0050] According to another aspect of the disclosed technology, the dual-frequency matching circuit 106a may include one or more signal monitors configured to monitor various signal levels of the RF power provided by the matching circuit. For example, a first phase-amplitude detector 134 may be coupled between the first input port 120 and the first circuit portion 122, and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the first input port 120 at a first frequency. A second phase-amplitude detector 154 may be coupled between the second input port 140 and the second circuit portion 142, and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the second input port 140 at a second frequency. A first voltage-current (VI) probe 136 may be coupled between the first circuit portion 122 (e.g., in the first series inductor 132) and the first output port 138, and may be configured to measure the RF voltage and RF current of a first output signal (e.g., the first output signal 107 of FIG. 1). The second VI probe 156 can be coupled between the second circuit section 142 (e.g., the second parallel capacitor 150) and the second output port 158, and can be configured to measure the RF voltage and RF current of the second output signal (e.g., the second output signal 109 of FIG1).

[0051] In some implementations, the amplitude and / or phase values ​​determined by various signal monitors (e.g., first amplitude detector 134, second amplitude detector 154, first VI probe 136, and second VI probe 156) can be evaluated periodically or continuously to ensure the correct values ​​of the frequency tuning elements in the matching circuit 106a. The values ​​of some tuning elements (e.g., variable capacitors such as first parallel capacitor 126, first series capacitor 130, second series capacitor 146, and second parallel capacitor 150) can be periodically tuned based on the values ​​determined by the signal monitors.

[0052] FIG3 depicts a second exemplary dual-frequency matching circuit 106b according to an exemplary embodiment of the present disclosure. The dual-frequency matching circuit 106b includes a first input port 220, a matching circuit 221, a first circuit portion 222, a first bypass filter element 224, a physical housing 225, a first parallel capacitor 226, a first series capacitor 228, a first phase amplitude detector 234, a first VI probe 236, a first output port 238, a second input port 240, a second circuit portion 242, a second bypass filter element 244, a second series capacitor 246, a second parallel capacitor 248, a second phase amplitude detector 254, a second VI probe 256, a second output port 258, and a distance 260.

[0053] The first input port 220 can be configured to receive RF power at a first frequency (e.g., the first RF power 103 of FIG. 1), and the second input port 240 can be configured to receive RF power at a second frequency different from the first frequency (e.g., the second RF power 105 of FIG. 1). The dual-frequency matching circuit 106b may include a matching circuit 221, which includes a first circuit portion 222 and a second circuit portion 242 housed together in a single physical housing 225. The first circuit portion 222 may include one or more first tuning elements (e.g., a first parallel capacitor 226 and a first series capacitor 228) configured to receive RF power at the first input port 220 and provide impedance matching for a first load (e.g., the first ICP load 108 of FIG. 1). The second circuit portion 242 may include one or more second tuning elements (e.g., a second series capacitor 246 and a second parallel capacitor 248) configured to receive RF power at the second input port 240 and provide impedance matching for a second load (e.g., the second ICP load 110 of FIG. 1). The first output port 238 may be coupled to a first circuit portion 222 of the matching circuit 221 and may be configured to provide a first output signal to a first load (e.g., a first ICP load 108) at a first frequency. The second output port 258 may be coupled to a second circuit portion 242 of the matching circuit 221 and may be configured to provide a second output signal to a second load (e.g., a second ICP load 110) at a second frequency. In some implementations, the first output port 238 and the second output port 258 may be spaced apart from each other by a distance 260, which may be selected within a range of about 1 inch to about 35 inches.

[0054] Still referring to FIG. 3, the components of the matching circuit 106b are configured to be housed together in a single, single physical housing 225. For example, the physical housing 225 may house a first phase amplitude detector 234, a second phase amplitude detector 254, a matching circuit 221 including a first circuit portion 222 and a second circuit portion 242, a first VI probe 236, and a second VI probe 256. In some examples, one or more metal partitions 227 may be provided within the single physical housing 225 to ensure positioning and physical separation between each circuit portion. In the dual-frequency implementation of FIG. 3, the metal partitions 227 may be positioned between and physically space the first circuit portion 222 and the second circuit portion 242.

[0055] According to another aspect of the disclosed technology, the first circuit portion 222 and the second circuit portion 242 in the matching circuit 221 may include corresponding bypass filter elements (e.g., first bypass filter element 224 and second bypass filter element 244) configured to filter out residual power at frequencies other than those used for a given circuit portion. The first bypass filter element 224 may be provided between, for example, a first input port 220 and one or more first tuning elements, and may be configured to filter out residual power leaking to the first circuit portion 222 at a second frequency (e.g., about 2 MHz). The second bypass filter element 244 may be provided between, for example, a second input port 240 and one or more second tuning elements, and may be configured to filter out residual power leaking to the second circuit portion 242 at a first frequency (e.g., about 13.56 MHz). The first bypass filter element 224 and the second bypass filter element 244 may each correspond to one or more passive circuit elements, such as, but not limited to, capacitors and / or inductors. In a particular implementation, for example, the first bypass filter element 224 may be an inductor, while the second bypass filter element 244 may be a capacitor.

[0056] Still referring to FIG. 3, one or more tuning elements in each of the first circuit section 222 and the second circuit section 242 of the matching circuit 106b can take various specific configurations. For example, one or more first tuning elements in the first circuit section 222 may include a first parallel capacitor 226 and a first series capacitor 228, one or both of which may correspond to a variable capacitor. The first parallel capacitor 226 is positioned in parallel with the first bypass filter element 224 and before the first series capacitor 228. The first series capacitor 228 is positioned between the first parallel capacitor 226 and the output port 138. Example ranges of values ​​for the elements in the first circuit section 222 may include: an inductance value of the first bypass filter element 224 between about 1 μH and about 5 μH, a capacitance value of the first parallel capacitor 226 between about 20 pF and about 2,000 pF, and a capacitance value of the first series capacitor 228 between about 5 pF and about 500 pF.

[0057] One or more second tuning elements in the second circuit section 242 may include a second parallel capacitor 248 and a second series capacitor 246, one or both of which may correspond to a variable capacitor. The second parallel capacitor 248 is positioned in parallel with a second bypass filter element 244, and the second series capacitor 246 is located between the second parallel capacitor 248 and the second bypass filter element 244. Example ranges of values ​​for the elements in the second circuit section 242 may include: a capacitance value of the second bypass filter element 244 between approximately 0 pF and approximately 500 pF, a capacitance value of the second series capacitor 246 between approximately 50 pF and approximately 10 nF, and a capacitance value of the second parallel capacitor 248 between approximately 50 pF and approximately 10 nF.

[0058] According to another aspect of the disclosed technology, the matching circuit 106b may include one or more signal monitors configured to monitor various signal levels of the RF power provided by the matching circuit. For example, a first phase-amplitude detector 234 may be coupled between the first input port 220 and the first circuit portion 222, and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the first input port 220 at a first frequency. A second phase-amplitude detector 254 may be coupled between the second input port 240 and the second circuit portion 242, and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the second input port 240 at a second frequency. A first voltage-current (VI) probe 236 may be coupled between the first circuit portion 222 (e.g., the first series capacitor 228) and the first output port 238, and may be configured to measure the RF voltage and RF current of a first output signal (e.g., the first output signal 107 of FIG. 1). The second VI probe 256 can be coupled between the second circuit section 242 (e.g., the second parallel capacitor 248) and the second output port 258, and can be configured to measure the RF voltage and RF current of the second output signal (e.g., the second output signal 109 of FIG. 1).

[0059] In some implementations, the amplitude and / or phase values ​​determined by various signal monitors (e.g., first amplitude detector 234, second amplitude detector 254, first VI probe 236, and second VI probe 256) can be evaluated periodically or continuously to ensure the correct values ​​of the frequency tuning elements in the dual-frequency matching circuit 106b. The values ​​of some tuning elements (e.g., variable capacitors such as first parallel capacitor 226, first series capacitor 228, second series capacitor 246, and second parallel capacitor 248) can be periodically tuned based on the values ​​determined by the signal monitors.

[0060] FIG4 depicts a third exemplary dual-frequency matching circuit 106c according to an exemplary embodiment of the present disclosure. The dual-frequency matching circuit 106c includes a first input port 320, a matching circuit 321, a first circuit portion 322, a first bypass filter element 324, a physical housing 325, a first series capacitor 326, a first parallel capacitor 328, a first phase amplitude detector 334, a first V1 probe 336, a first output port 338, a second input port 340, a second circuit portion 342, a second bypass filter element 344, a second series capacitor 346, a second parallel capacitor 348, a second phase amplitude detector 354, a second probe 356, a second output port 358, and a distance 360.

[0061] The first input port 320 can be configured to receive RF power at a first frequency (e.g., the first RF power 103 of FIG. 1), and the second input port 340 can be configured to receive RF power at a second frequency different from the first frequency (e.g., the second RF power 105 of FIG. 1). The dual-frequency matching circuit 106c may include a matching circuit 321, which includes a first circuit portion 322 and a second circuit portion 342 housed together in a single physical housing 325. The first circuit portion 322 may include one or more first tuning elements (e.g., a first series capacitor 326 and a first parallel capacitor 328) configured to receive RF power at the first input port 320 and provide impedance matching for a first load (e.g., the first ICP load 108 of FIG. 1). The second circuit portion 342 may include one or more second tuning elements (e.g., a second series capacitor 346 and a second parallel capacitor 348) configured to receive RF power at the second input port 340 and provide impedance matching for a second load (e.g., the second ICP load 110 of FIG. 1). The first output port 338 may be coupled to a first circuit portion 322 of the matching circuit 321 and may be configured to provide a first output signal to a first load (e.g., the first ICP load 108 of FIG. 1) at a first frequency. The second output port 358 may be coupled to a second circuit portion 342 of the matching circuit 321 and may be configured to provide a second output signal to a second load (e.g., the second ICP load 110 of FIG. 1) at a second frequency. In some implementations, the first output port 338 and the second output port 358 may be spaced apart from each other by a distance 360, which may be selected within a range of about 1 inch to about 35 inches.

[0062] Still referring to FIG. 4, the components of the matching circuit 106c are configured to be housed together in a single physical housing 325. For example, the physical housing 325 may house a first phase amplitude detector 334, a second phase amplitude detector 354, a matching circuit 321 including a first circuit portion 322 and a second circuit portion 342, a first VI probe 336, and a second VI probe 356. In some examples, one or more metal partitions 327 may be provided within the single physical housing 325 to ensure positioning and physical separation between each circuit portion. In the dual-frequency implementation of FIG. 4, the metal partitions 327 may be positioned between and physically space the first circuit portion 322 and the second circuit portion 342.

[0063] According to another aspect of the disclosed technology, the first circuit portion 322 and the second circuit portion 342 in the matching circuit 321 may include corresponding bypass filter elements (e.g., first bypass filter element 324 and second bypass filter element 344) configured to filter out residual power at frequencies other than those used for a given circuit portion. The first bypass filter element 324 may be provided between, for example, the first input port 320 and one or more first tuning elements, and may be configured to filter out residual power leaking to the first circuit portion 322 at a second frequency (e.g., about 2 MHz). The second bypass filter element 344 may be provided between, for example, the second input port 340 and one or more second tuning elements, and may be configured to filter out residual power leaking to the second circuit portion 342 at a first frequency (e.g., about 13.56 MHz). The first bypass filter element 324 and the second bypass filter element 344 may each correspond to one or more passive circuit elements, such as, but not limited to, capacitors and / or inductors. In a particular implementation, for example, the first bypass filter element 324 may be an inductor, while the second bypass filter element 344 may be a capacitor.

[0064] Still referring to FIG. 4, one or more tuning elements in each of the first circuit section 322 and the second circuit section 342 of the matching circuit 106c can take various specific configurations. For example, one or more first tuning elements in the first circuit section 322 may include a first series capacitor 326 and a first parallel capacitor 328, one or both of which may correspond to a variable capacitor. The first parallel capacitor 328 in the first circuit section 322 is located between the series capacitor 326 and the first output port 338 in the first circuit section 322. Example ranges of values ​​for the elements in the first circuit section 322 may include: an inductance value of the first bypass filter element 324 between about 1 μH and about 5 μH, a capacitance value of the first parallel capacitor 328 between about 20 pF and about 2000 pF, and a capacitance value of the first series capacitor 326 between about 5 pF and about 500 pF.

[0065] One or more second tuning elements in the second circuit section 342 may include a second parallel capacitor 348 and a second series capacitor 346, one or both of which may correspond to a variable capacitor. The second parallel capacitor 348 in the second circuit section 342 is positioned between the series capacitor 346 and the second output port 358 in the second circuit section 342. Example ranges of values ​​for the elements in the second circuit section 342 may include: a capacitance value of the second bypass filter element 344 between approximately 0 pF and approximately 500 pF; a capacitance value of the second series capacitor 346 between approximately 50 pF and approximately 10 nF; and a capacitance value of the second parallel capacitor 348 between approximately 50 pF and approximately 10 nF.

[0066] According to another aspect of the disclosed technology, the matching circuit 106c may include one or more signal monitors configured to monitor various signal levels of the RF power provided by the matching circuit. For example, a first phase-amplitude detector 334 may be coupled between the first input port 320 and the first circuit portion 322 and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the first input port 320 at a first frequency. A second phase-amplitude detector 354 may be coupled between the second input port 340 and the second circuit portion 342 and may be configured to measure the RF voltage, RF current, and the phase angle between the RF voltage and RF current of the RF power provided to the second input port 340 at a second frequency. A first voltage-current (VI) probe 336 may be coupled between the first circuit portion 322 (e.g., the first parallel capacitor 328) and the first output port 338 and may be configured to measure the RF voltage and RF current of a first output signal (e.g., the first output signal 107 of FIG. 1). The second VI probe 356 can be coupled between the second circuit section 342 (e.g., the second parallel capacitor 348) and the second output port 358, and can be configured to measure the RF voltage and RF current of the second output signal (e.g., the second output signal 109 of FIG1).

[0067] In some implementations, the amplitude and / or phase values ​​determined by various signal monitors (e.g., first amplitude detector 334, second amplitude detector 354, first VI probe 336, and second VI probe 356) can be evaluated periodically or continuously to ensure the correct values ​​of the frequency tuning elements in the matching circuit 106c. The values ​​of some tuning elements (e.g., variable capacitors such as first series capacitor 326, first parallel capacitor 328, second series capacitor 346, and second parallel capacitor 348) can be periodically tuned based on the values ​​determined by the signal monitors.

[0068] FIG5 depicts a plasma processing apparatus 400 according to an exemplary embodiment of the present disclosure. The plasma processing apparatus 400 includes a processing chamber defining an internal space 402. A base or substrate support 404 is used to support a substrate 406, such as a semiconductor wafer, within the internal space 402. A dielectric window 410 is located above the substrate support 404. The dielectric window 410 includes a relatively flat central portion 412 and an angled peripheral portion 414. The dielectric window 410 includes a space in the central portion 412 for a nozzle 420 to deliver process gas into the internal space 402.

[0069] The plasma processing apparatus 400 further includes a plurality of sensing elements, such as a main sensing element 430 and an auxiliary sensing element 440, for generating induced plasma in the internal space 402. The main sensing element 430 and the auxiliary sensing element 440 may each include a coil or an antenna element that induces plasma in the process gas of the internal space 402 of the plasma processing apparatus 400 when the coil or antenna element is supplied with RF power. For example, a first RF generator 102 may be configured to provide electromagnetic energy to the main sensing element 430 via a matching circuit 106. A second RF generator 104 may be configured to provide electromagnetic energy to the auxiliary sensing element 440 via the same matching circuit 106.

[0070] Although this disclosure refers to a primary sensing element 430 and an auxiliary sensing element 440, those skilled in the art will understand that the terms "primary" and "auxiliary" are used for convenience only. An auxiliary sensing element may operate independently of the primary element, and vice versa. Furthermore, an additional sensing element (e.g., a third sensing element) having a corresponding matching circuit provided in the matching circuit 106 may be included in the plasma processing apparatus 400.

[0071] According to various aspects of this disclosure, the plasma processing apparatus 400 may include a metal shield portion 452 disposed around the auxiliary sensing element 440. As discussed in detail below, the metal shield portion 452 spaces the main sensing element 430 and the auxiliary sensing element 440 to reduce crosstalk between the main sensing element 430 and the auxiliary sensing element 440. The plasma processing apparatus 400 may further include a Faraday shield portion 454 disposed between the main sensing element 430 and the dielectric window 410. The Faraday shield portion 454 may be a slotted metal shield that reduces capacitive coupling between the main sensing element 430 and the internal space 402. As shown, the Faraday shield portion 454 may be mounted on an angled portion of the dielectric window 410.

[0072] In a particular embodiment, the metal shield portion 452 and the Faraday shield portion 454 may form a single shield body 450 for ease of manufacture and other purposes. FIG5 illustrates a single shield body 450 for use in an exemplary embodiment of the metal shield portion 452 and the Faraday shield portion 454 according to an exemplary embodiment of the present disclosure. The multi-turn coil of the main sensing element 430 may be located near the Faraday shield portion 454 of the single shield body 450. The auxiliary sensing element 440 may be located near the metal shield portion 452 of the single shield body 450, for example, between the metal shield portion 452 and the dielectric window 410.

[0073] The arrangement of the main sensing element 430 and the auxiliary sensing element 440 on opposite sides of the metal shield portion 452 allows the main sensing element 430 and the auxiliary sensing element 440 to have different structural configurations and perform different functions. For example, the main sensing element 430 may include a multi-turn coil located near the peripheral portion of the processing chamber. The main sensing element 430 can be used for basic plasma generation and reliable startup during the inherent transient ignition phase. The main sensing element 430 can be coupled to a powerful RF generator 102 and can operate at increased RF frequencies, such as approximately 13.56 MHz.

[0074] The auxiliary sensing element 440 can be used for correction and support functions, as well as to improve plasma stability during steady-state operation. Since the auxiliary sensing element 440 can primarily be used for correction and support functions and to improve plasma stability during steady-state operation, it does not need to be coupled to a powerful RF generator like the main sensing element 430, and can be designed in a different and cost-effective manner to overcome difficulties associated with previous designs. As discussed in detail below, the auxiliary sensing element 440 can also be coupled to the RF generator 104 and configured to operate at a lower frequency, such as around 2 MHz, thereby making the auxiliary sensing element 440 very compact and mounted within a limited space at the top of the dielectric window.

[0075] According to an exemplary aspect of this disclosure, the primary sensing element 430 and the secondary sensing element 440 operate at different frequencies. These frequencies are significantly different to reduce crosstalk between the primary sensing element 430 and the secondary sensing element 440. For example, the frequency applied from the matching circuit 106 to the primary sensing element 430 may be at least about 1.5 times greater than the frequency applied to the secondary sensing element 440. In a particular embodiment, the frequency applied to the primary sensing element 430 may be in the range of about 12.75 MHz to about 14.25 MHz (e.g., about 13.56 MHz), and the frequency applied to the secondary sensing element 440 may be in the range of about 1.75 MHz to about 2.15 MHz (e.g., about 2 MHz). Other suitable frequencies, such as about 400 kHz, about 4 MHz, and about 27 MHz, may also be used. Although this disclosure is discussed with reference to the operation of the primary sensing element 430 relative to the secondary sensing element 440 at a higher frequency, those skilled in the art using the disclosure provided herein should understand that the secondary sensing element 440 may operate at a higher frequency without departing from the scope of this disclosure.

[0076] Because different frequencies can be applied to the main sensing element 430 and the auxiliary sensing element 440, interference between the sensing elements 430 and 440 is reduced. More specifically, the only interaction in the plasma between the sensing elements 430 and 440 is through plasma density. Therefore, phase synchronization is not required between the RF generator 102 coupled to the main sensing element 430 and the RF generator 104 coupled to the auxiliary sensing element 440. Power control is independent between the sensing elements. Furthermore, since the sensing elements 430 and 440 operate at significantly different frequencies, it is feasible to use frequency tuning of the RF generators 102 and 104 in the integrated matching circuit 106 to match the power delivery to the plasma, which greatly simplifies the design, cost, and maintainability of the entire system.

[0077] Compared to the main inductor 430 operating at 13.56 MHz, the auxiliary inductor 440 can operate at approximately 2 MHz and can have more turns, thus operating at a lower current amplitude: where is the coil current, is the power deposited by the coil in the plasma, is the plasma resistance, and is the number of turns of the coil. The low current allows the use of ordinary medium-gauge wire in the coil, rather than large-gauge wire or copper tubing.

[0078] Due to the lower operating frequency (f), the auxiliary sensing element 440 with inductance L does not need to operate at the same high voltage as a coil of the same diameter D operating at a higher frequency (assuming it deposits the same power into the plasma and produces plasma with the same parameters); moreover, due to the smaller diameter, the voltage is much lower than the voltage used to drive the first coil. Since the auxiliary sensing element 440 can operate at lower voltages and currents, the auxiliary sensing element 440 can have a compact design that can be embedded into the Faraday shield portion 454.

[0079] According to various aspects of this disclosure, sensing elements 430 and 440 can perform different functions. Specifically, only the main sensing element 430 can be responsible for performing the most important function of generating plasma during ignition and providing sufficient actuation for the auxiliary sensing element 440. This main sensing element 430 can participate in the operation of the ICP tool and should be coupled to both the plasma and the ground shield to stabilize the plasma potential. The Faraday shield portion 454 associated with the main sensing element 430 avoids window sputtering and can be used to provide coupling to ground.

[0080] The auxiliary coil can operate with good plasma initiation provided by the main induction element 430; therefore, it preferably has good plasma coupling and good energy transfer efficiency to the plasma. The auxiliary induction element 440, including the flux concentrator 444, provides both good transfer of flux to the plasma volume and good decoupling between the auxiliary induction element 440 and the surrounding metal shielding portion 452. The symmetrical drive of the flux concentrator 444 and the auxiliary induction element 440 further reduces the voltage amplitude between the coil ends and the surrounding grounding elements. This effectively eliminates sputtering of the dome, but at the same time provides some small capacitive coupling to the plasma, which can be used to aid ignition.

[0081] The ICP source used in the plasma processing apparatus 400 exhibits very robust light source behavior and a very wide processing window. In most process gases, including “difficult” gases like pure HBr or SF6, the source can easily ignite and sustain plasma with a total power significantly lower than that required using only a single coil. These discharges can even be sustained without any bias power. In fact, the exemplary induction element arrangement of this disclosure actually shows better stability and efficiency compared to sources using only one coil or multiple coils with similar structures. Despite numerous attempts, the instabilities associated with discharges in electronegative gases, often observed in other ICP reactors, have not been detected.

[0082] These and other modifications and variations to the invention can be made by those skilled in the art without departing from the spirit and scope of the invention, which are set forth in more detail in the appended claims. Furthermore, it should be understood that various aspects of the embodiments can be interchanged in whole or in part. Moreover, those skilled in the art will understand that the above description is merely illustrative and not intended to limit the invention further described in the appended claims. [Simplified Explanation of the Diagram]

[0011] The remainder of the specification, including the accompanying drawings, sets forth in more detail a full and practicable disclosure (including the best mode) that will be apparent to those skilled in the art, wherein:

[0012] FIG1 depicts a block diagram of a power generation system according to an exemplary embodiment of the present disclosure;

[0013] FIG2 depicts a first exemplary dual-frequency matching circuit according to an exemplary embodiment of the present disclosure;

[0014] FIG3 depicts a second exemplary dual-frequency matching circuit according to an exemplary embodiment of the present disclosure;

[0015] FIG4 depicts a third exemplary dual-frequency matching circuit according to an exemplary embodiment of the present disclosure; and

[0016] FIG5 depicts a plasma processing apparatus according to an exemplary embodiment of the present disclosure.

Claims

1. A dual-frequency matching circuit, comprising: The first input port is configured to receive RF power at a first frequency; The second input port is configured to receive RF power at a second frequency, which is different from the first frequency. A matching circuit, provided in a single physical housing, includes: a first circuit portion including one or more first tuning elements configured to receive RF power at a first input port and provide impedance matching for a first load; and a second circuit portion including one or more second tuning elements configured to receive RF power at a second input port and provide impedance matching for a second load; a first voltage-current probe coupled between the first circuit portion and a first output port, the first voltage-current probe being configured to measure the RF voltage and RF current of a first output signal; and a second voltage-current probe coupled between the second circuit portion and the second output port, the second voltage-current probe being configured to measure the RF voltage and RF current of a second output signal; and a first output port coupled to the first circuit portion of the matching circuit and configured to provide the first output signal to the first load at a first frequency; And the second output port, coupled to the second circuit portion of the matching circuit, and configured to provide the second output signal to the second load at the second frequency.

2. The dual-frequency matching circuit according to claim 1, wherein the matching circuit comprises: A first bypass filter element is provided between the first input port and the one or more first tuning elements, the first bypass filter element being configured to filter out residual power at the second frequency that leaks into the first circuit portion; And a second bypass filter element provided between the second input port and the one or more second tuning elements, the second bypass filter element being configured to filter out residual power at the first frequency leaking into the second circuit portion.

3. The dual-frequency matching circuit according to claim 2, wherein: The first bypass filter element includes an inductor; and the second bypass filter element includes a capacitor.

4. The dual-frequency matching circuit according to claim 2, wherein, Each of the one or more first tuning elements and the one or more second tuning elements includes a parallel capacitor and a series capacitor, respectively.

5. The dual-frequency matching circuit according to claim 4, wherein, Each of the one or more first tuning elements and the one or more second tuning elements respectively includes a series inductor.

6. The dual-frequency matching circuit according to claim 4, wherein: The parallel capacitor in the first circuit section is positioned between the first bypass filter element and the series capacitor in the first circuit section; The parallel capacitor in the second circuit section is positioned between the second bypass filter element and the series capacitor in the second circuit section.

7. The dual-frequency matching circuit according to claim 4, wherein: The parallel capacitor in the first circuit section is positioned between the series capacitor in the first circuit section and the first output port; The parallel capacitor in the second circuit section is positioned between the series capacitor in the second circuit section and the second output port.

8. The dual-frequency matching circuit according to claim 1, wherein the matching circuit comprises: A first phase-amplitude detector is coupled between the first input port and the first circuit section, and the first phase-amplitude detector is configured to measure the phase angle between the RF voltage, the RF current, and the RF power at the first frequency; And a second phase-amplitude detector, coupled between the second input port and the second circuit section, the second phase-amplitude detector being configured to measure the phase angle between the RF voltage, the RF current and the RF power at the second frequency.

9. The dual-frequency matching circuit according to claim 1, comprising a metal partition in the single physical housing of the matching circuit, the metal partition being positioned between and physically spaced between the first circuit portion and the second circuit portion.

10. The dual-frequency matching circuit according to claim 1, wherein, The first output signal and the second output signal are respectively configured to provide pulsed RF power.

11. The dual-frequency matching circuit according to claim 1, wherein, The first frequency is in the range of about 12.75 MHz to about 14.25 MHz, and the second frequency is in the range of about 1.75 MHz to about 2.15 MHz.

12. The dual-frequency matching circuit according to claim 1, wherein, The first output signal is provided at a power level in the range of about 1 kW to about 5 kW, and the second output signal is provided at a power level in the range of about 500 watts to about 3 kW.

13. A power generation system for an inductively coupled plasma load, comprising: A first RF generator is configured to provide electromagnetic energy at a first frequency in either continuous or pulsed mode. A second RF generator is configured to provide electromagnetic energy at a second frequency in either continuous or pulsed mode, wherein the second frequency is different from the first frequency. A matching circuit includes: a first circuit portion of one or more first tuning elements configured to receive electromagnetic energy at a first frequency and provide impedance matching for a first inductively coupled plasma load; and a second circuit portion of one or more second tuning elements configured to receive electromagnetic energy at a second frequency and provide impedance matching for a second inductively coupled plasma load; a first voltage-current probe coupled between the first circuit portion and the first inductively coupled plasma load, the first voltage-current probe being configured to measure an RF voltage and an RF current of a first output signal provided to the first inductively coupled plasma load; and a second voltage-current probe coupled between the second circuit portion and the second inductively coupled plasma load, the second voltage-current probe being configured to measure an RF voltage and an RF current of a second output signal provided to the second inductively coupled plasma load; and a single solid housing housing the first circuit portion and the second circuit portion.

14. The power generation system according to claim 13, wherein: The first circuit portion includes a first bypass filter element disposed before the one or more first tuning elements, the first bypass filter element being configured to filter out residual power at the second frequency leaking into the first circuit portion; The second circuit portion includes a second bypass filter element disposed before the one or more second tuning elements, the second bypass filter element being configured to filter out residual power at the first frequency leaking into the second circuit portion.

15. The power generation system according to claim 13, wherein the matching circuit comprises: A first phase-amplitude detector, coupled to the first circuit portion, is configured to measure RF voltage, RF current, and the phase angle between the RF voltage and the RF current of the electromagnetic energy at the first frequency; And a second phase amplitude detector, coupled to the second circuit portion, the second phase amplitude detector being configured to measure RF voltage, RF current, and the phase angle between the RF voltage and the RF current of the electromagnetic energy at the second frequency.

16. The power generation system according to claim 13, comprising a metal partition within the single solid housing, the metal partition being positioned between and physically separating the first circuit portion and the second circuit portion.

17. The power generation system according to claim 13, wherein: The electromagnetic energy provided at the first frequency is provided at a power level in the range of about 1 kW to about 5 kW and a frequency in the range of about 12.75 MHz to about 14.25 MHz; and the electromagnetic energy provided at the second frequency is provided at a power level in the range of about 500 watts to about 3 kW and a frequency in the range of about 1.75 MHz to about 2.15 MHz.

18. A plasma treatment apparatus, comprising: The processing chamber has an internal space operable to receive process gases; A base support, within the internal space of the processing chamber, is operable to hold the base. The first sensing element and the second sensing element are located at different positions relative to the processing chamber; The system also includes a matching circuit, provided in a single physical housing, comprising: a first circuit portion of one or more first tuning elements configured to receive RF power at a first frequency and provide impedance matching for a first inductively coupled plasma load including the first sensing element; a second circuit portion of one or more second tuning elements configured to receive RF power at a second frequency and provide impedance matching for a second inductively coupled plasma load including the second sensing element, wherein the second frequency is different from the first frequency; a first voltage-current probe coupled between the first circuit portion and the first inductively coupled plasma load, the first voltage-current probe being configured to measure the RF voltage and RF current of a first output signal provided to the first inductively coupled plasma load; and a second voltage-current probe coupled between the second circuit portion and the second inductively coupled plasma load, the second voltage-current probe being configured to measure the RF voltage and RF current of a second output signal provided to the second inductively coupled plasma load.

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