Hardware switch for main feed line in radio frequency plasma processing chamber - Patents.com

Abstract

Embodiments provided herein generally include apparatus, such as, for example, a plasma processing system, and methods for plasma processing a substrate in a processing chamber. Some embodiments relate to a radio frequency (RF) generation system. The RF generation system generally includes an RF generator and a vacuum interrupter configured to selectively decouple the RF generator from a bias electrode of a plasma chamber based on detection of a fault condition related to operation of the plasma chamber.

Description

[Technical field]

[0001] background Field

[0001] 1. Field of the Invention

[0002] Embodiments of the present disclosure relate generally to systems used in the manufacture of semiconductor devices. More particularly, embodiments of the present disclosure relate to plasma processing systems used to process substrates. [Background technology]

[0002] 2. Description of Related Art One method of forming high aspect ratio features uses a plasma-assisted etch process that bombards material formed on a surface of a substrate through openings formed in a patterned mask layer on the substrate surface. In a typical plasma-assisted etch process, a substrate is placed on an electrostatic chuck (ESC) disposed in a process chamber, a plasma is formed over the substrate, and ions are accelerated from the plasma toward the substrate through a plasma sheath, i.e., an electron-depleted region, formed between the plasma and the surface of the substrate. To maintain the sheath in the plasma chamber, a radio frequency (RF) signal may be generated by an RF generation system. In some scenarios, a fault condition may occur when providing an RF signal to the plasma chamber, which may result in damage to the RF generation system. Thus, there is a need in the art for an RF generation system that can protect system hardware from potential fault conditions and increase system safety. Summary of the Invention

[0003]

[0003] Embodiments provided herein generally include apparatus, such as plasma processing systems, and methods for plasma processing a substrate in a processing chamber.

[0004] Some embodiments relate to a radio frequency (RF) generation system that typically includes an RF generator and a vacuum interrupter configured to selectively decouple the RF generator from a bias electrode of a plasma chamber based on detection of a fault condition associated with operation of the plasma chamber.

[0005] Some embodiments relate to a plasma processing method that generally includes generating an RF signal that is provided to a bias electrode of a plasma chamber via an RF generator, detecting a fault condition related to operation of the plasma chamber, and decoupling the RF generator from the bias electrode of the plasma chamber via a vacuum interrupter based on the detection of the fault condition.

[0006] Some embodiments relate to an apparatus for plasma processing that generally includes means for generating an RF signal provided to a bias electrode of a plasma chamber, means for detecting a fault condition related to operation of the plasma chamber, and a vacuum interrupter configured to decouple a first RF generator from the bias electrode of the plasma chamber based on detection of the fault condition.

[0007]

[0007] So that the above features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above can be had by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings depict only exemplary embodiments, and therefore should not be considered as limiting the scope of the present disclosure, as other equally effective embodiments may be permitted. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view of a processing system according to one or more embodiments configured to perform the methods described herein. [Diagram 2]

[0009] 1 illustrates a radio frequency (RF) generating system according to certain embodiments of the present disclosure. [Diagram 3]

[0010] 1 shows an implementation of a hardware switch using a vacuum interrupter. [Figure 4]

[0011] Here is an example of an RF matching circuit. [Diagram 5]

[0012] FIG. 1 is a process flow diagram illustrating a plasma processing method according to certain embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009]

[0013] Certain aspects of the present disclosure generally relate to a radio frequency (RF) generation system implemented using a hardware switch. The hardware switch may be implemented as a vacuum interrupter to facilitate decoupling of the RF generator from a complex load located within a plasma processing chamber to enhance system safety and prevent damage to the RF generation system. A controller may be used to control the hardware switch to decouple the RF generator from the plasma generator when a fault or reflected power that would damage the RF generation system is detected. For example, the hardware switch may be opened when a sudden change in voltage, current, or impedance is detected. The vacuum interrupter provides various benefits including hardware protection from fault conditions and improved safety by isolating the RF generator from the plasma processing chamber during maintenance. Because the hardware switch operates in a vacuum, the vacuum interrupter provides a well-defined arcing point when the hardware switch is opened, which helps to avoid potential damage to components within the RF generation system and other systems located within the plasma processing chamber.

[0010] Plasma Processing System Examples

[0014] 1 is a schematic cross-sectional view of a processing system 10 configured to perform one or more plasma processing methods described herein. In some embodiments, the processing system 10 is configured for a plasma-assisted etch process, such as a reactive ion etch (RIE) plasma process. However, it should be noted that the embodiments described herein may also be used in processing systems configured for use in other plasma-assisted processes, such as plasma-enhanced deposition processes, such as plasma-enhanced chemical vapor deposition (PECVD) processes, plasma-enhanced physical vapor deposition (PEPVD) processes, plasma-enhanced atomic layer deposition (PEALD) processes, plasma treatment processes, such as plasma doping (PLAD), or plasma-based ion implantation processes.

[0011]

[0015] As shown, the processing system 10 is configured to form a capacitively coupled plasma (CCP), and the processing chamber 100 includes an upper electrode (e.g., chamber lid 123) disposed in a processing volume 129 facing a lower electrode (e.g., substrate support assembly 136) disposed within the processing volume 129. In a typical capacitively coupled plasma (CCP) processing system, a radio frequency (RF) source (e.g., RF generator 118) is electrically coupled to one of the upper or lower electrodes and delivers an RF signal configured to ignite and sustain a plasma (e.g., plasma 101). In this configuration, the plasma is capacitively coupled to each of the upper and lower electrodes and disposed in the processing volume between them. Typically, the opposing one of the upper or lower electrodes is coupled to ground or a second RF power source. One or more components of the substrate support assembly 136, such as the support base 107, are electrically coupled to a plasma generator assembly 163, which includes the RF generator 118, and the chamber lid 123 is electrically coupled to electrical ground. As shown, the processing system 10 includes a processing chamber 100 , a support assembly 136 , and a system controller 126 .

[0012]

[0016] The processing chamber 100 typically includes a chamber body 113 including a chamber lid 123, one or more sidewalls 122, and a chamber base 124, which collectively define a processing region 129. The one or more sidewalls 122 and the chamber base 124 are generally sized and shaped to provide structural support for the elements of the processing chamber 100 and comprise a material configured to withstand pressure and additional energy applied thereto while the plasma 101 is generated within a vacuum environment that is maintained within the processing region 129 of the processing chamber 100 during processing. In one example, the one or more sidewalls 122 and the chamber base 124 are formed from a metal, such as aluminum, an aluminum alloy, or a stainless steel alloy.

[0013]

[0017] A gas inlet 128 disposed through the chamber lid 123 is used to supply one or more process gases from a process gas source 119 in fluid communication with the process region 129. The substrate 103 is loaded into the process region 129 through an opening (not shown) in one or more sidewalls 122 and removed from the process region 129 and sealed with a slit valve (not shown) during plasma processing of the substrate 103.

[0014]

[0018] The system controller 126, also referred to herein as a process chamber controller, includes a central processing unit (CPU) 133, a memory 134, and support circuits 135. The system controller 126 is used to control the process sequence used to process the substrate 103, including the substrate bias method described herein. The CPU 133 is a general-purpose computer processor configured for use in an industrial environment to control the process chamber and its associated sub-processors. The memory 134 described herein is generally non-volatile memory and may include random access memory, read-only memory, floppy or hard disk drives, or other suitable forms of digital storage, local or remote. The support circuits 135 are conventionally coupled to the CPU 133 and include caches, clock circuits, input / output subsystems, power supplies, and the like, and combinations thereof. Software instructions (programs) and data may be coded and stored in the memory 134 to instruct the processor in the CPU 133. The software programs (or computer instructions) readable by the CPU 133 in the system controller 126 determine which tasks are executable by the components in the processing system 10.

[0015]

[0019] Typically, a program readable by the CPU 133 of the system controller 126 includes code that, when executed by the processor (CPU 133), performs tasks related to the plasma processing schemes described herein. The program may include instructions used to control various hardware and electrical components within the processing system 10 to perform various process tasks and various process sequences used to implement the methods described herein. In one embodiment, the program includes instructions used to perform one or more operations described below in connection with FIG. 5.

[0016]

[0020] The processing system may include a plasma generator assembly 163, a first pulsed voltage (PV) source assembly 196 for establishing a first PV waveform at the bias electrode 104, and a second PV source assembly 197 for establishing a second PV waveform at the edge control electrode 115. In some embodiments, the plasma generator assembly 163 supplies an RF signal to the support base 107 (e.g., a powered electrode or cathode), which may be used to generate (sustain and / or ignite) a plasma 101 in a processing region 129A disposed between the substrate support assembly 136 and the chamber lid 123. In some embodiments, the RF generator 118 is configured to deliver an RF signal having a frequency of 1 MHz or greater, or about 2 MHz or greater, such as about 13.56 MHz or greater.

[0017]

[0021] As discussed above, in some embodiments, the plasma generator assembly 163, including the RF generator 118 and the RF generator assembly 160, is configured to supply a desired amount of continuous wave (CW) or pulsed RF power at a desired substantially fixed sinusoidal waveform frequency to the support base 107 of the substrate support assembly 136 based on control signals provided from the system controller 126. During processing, the plasma generator assembly 163 is configured to deliver RF power (e.g., an RF signal) to the support base 107 in the substrate support assembly 136 disposed proximate to the substrate support 105. The RF power supplied to the support base 107 is configured to ignite and maintain a processing plasma 101 of a processing gas disposed in the process space 129. Alternatively, in some embodiments, the first pulsed voltage (PV) source assembly 196 and the plasma generator assembly 163 are configured to supply a first PV waveform and an RF signal, respectively, to the bias electrode 104 of the substrate support assembly 136 during processing.

[0018]

[0022] In some embodiments, the support base 107 is an RF electrode electrically coupled to the RF generator 118 via an RF matching circuit 162 and a first filter assembly 161, both of which are disposed within the RF generator assembly 160. The first filter assembly 161 includes one or more electrical elements configured to substantially prevent current generated by the output of the PV waveform generator 150 from flowing through the RF power feed line 167 and damaging the RF generator 118. The first filter assembly 161 acts as a high impedance (e.g., high Z) to the PV signal generated from the PV pulse generator P1 in the PV waveform generator 150, and therefore, current flow to the RF matching circuit 162 and the RF generator 118 is inhibited.

[0019]

[0023] In some embodiments, the RF generator assembly 160 and the RF generator 118 are used to ignite and sustain a processing plasma 101 using a field generated by a processing gas disposed within the processing space 129 and RF power (RF signal) provided by the RF generator 118 to the support base 107. The processing region 129 is fluidly coupled to one or more dedicated vacuum pumps via a vacuum outlet 120, which maintain the processing region 129 at sub-atmospheric pressure conditions and evacuate the processing gas and / or other gases from the processing region 129. In some embodiments, a substrate support assembly 136 disposed within the processing region 129 is disposed on a support shaft 138 coupled to ground and extending through the chamber base 124. However, in some embodiments, the RF generator assembly 160 is configured to provide RF power to a bias electrode 104 disposed within the substrate support 105 rather than the support base 107.

[0020]

[0024] As described, in some embodiments, RF source power (e.g., from RF generator 118) for plasma generation is provided to an RF base plate (support base 107) in the cathode assembly, while the top electrode of the assembly is coupled to ground. The frequency of the RF source can be from 13.56 MHz to a high frequency band such as 60 MHz, 120 MHz, or 162 MHz. In some examples, the RF source power can also be provided through the top electrode. In some embodiments, the source can be operated in a pulsed mode. The pulse frequency can be 100 kHz to 5 kHz, and the duty cycle can be in the range of 5% to 95%. Bias power can be applied to the bottom electrode in the frequency range of 100 kHz to 20 MHz. The bias power can be operated in a continuous or pulsed mode. In some embodiments, there may be a third electrode (e.g., edge control electrode 115) at the edge of the cathode assembly for edge uniformity control. In some embodiments of the present disclosure, a switch 165 can be implemented between the RF generator 118 and the process chamber 100 for hardware protection and industrial safety.

[0021]

[0025] As briefly described above, the substrate support assembly 136 generally includes a substrate support 105 (e.g., an ESC substrate support) and a support base 107. In some embodiments, the substrate support assembly 136 may further include an insulating plate 111 and a ground plate 112, as further described below. The support base 107 is electrically isolated from the chamber base 124 by the insulating plate 111, and the ground plate 112 is interposed between the insulating plate 111 and the chamber base 124. The substrate support 105 is thermally coupled to and disposed on the support base 107. In some embodiments, the support base 107 is configured to regulate the temperature of the substrate support 105 and the substrate 103 disposed on the substrate support 105 during substrate processing.

[0022]

[0026] Typically, the substrate support 105 is formed of a dielectric material, such as a bulk sintered ceramic material, such as a corrosion resistant metal oxide or metal nitride material, such as aluminum oxide (Al2O3), aluminum nitride (AlN), titanium oxide (TiO), titanium nitride (TiN), yttrium oxide (Y2O3), mixtures thereof, or combinations thereof. In embodiments herein, the substrate support 105 further includes a bias electrode 104 embedded in the dielectric material. In some embodiments, one or more characteristics of the RF power used to maintain the plasma 101 in the processing region above the bias electrode 104 are determined and / or monitored by measuring an RF waveform established at the bias electrode 104.

[0023]

[0027] In one configuration, the bias electrode 104 is used as a chucking pole to secure (i.e., chuck) the substrate 103 to the substrate support surface 105A of the substrate support 105 and bias the substrate 103 relative to the processing plasma 101 using one or more pulsed voltage biasing schemes described herein. Typically, the bias electrode 104 is formed from one or more conductive components, such as one or more metal meshes, foils, plates, or combinations thereof.

[0024]

[0028] In some embodiments, the bias electrode 104 is electrically coupled to a clamp network 116 that supplies it with a chucking voltage, such as a static DC voltage between about -5000V and about 5000V, using an electrical conductor, such as a coaxial power supply 106 (e.g., a coaxial cable). As described further below, the clamp network 116 includes a bias compensation circuit element 116A, a DC power supply 155, and a blocking capacitor of the bias compensation module, also referred to herein as blocking capacitor C5. The blocking capacitor C5 is disposed between the output of the pulsed voltage (PV) waveform generator 150 and the bias electrode 104.

[0025]

[0029] The substrate support assembly 136 further includes an edge control electrode 115 located below the edge ring 114, surrounding the bias electrode 104, and / or spaced apart from the center of the bias electrode 104. Generally, for a processing chamber 100 configured to process a circular substrate, the edge control electrode 115 is annular in shape, made from a conductive material, and configured to surround at least a portion of the bias electrode 104. In some embodiments, such as shown in FIG. 1, the edge control electrode 115 is disposed within the region of the substrate support 105. In some embodiments, as shown in FIG. 1, the edge control electrode 115 includes a conductive mesh, foil, and / or plate disposed a similar distance (i.e., in the Z direction) from the substrate support surface 105A of the substrate support 105 as the bias electrode 104. In some other embodiments, the edge control electrode 115 includes a conductive mesh, foil, and / or plate disposed on or within a region of the quartz pipe 110, which surrounds at least a portion of the bias electrode 104 and / or the substrate support 105. Alternatively, in some other embodiments (not shown), the edge control electrode 115 is disposed within or coupled to an edge ring 114 that is disposed adjacent to the substrate support 105. In this configuration, the edge ring 114 is formed from a semiconductor or dielectric material (such as, for example, AlN).

[0026]

[0030] The edge control electrode 115 may be biased by using a different PV waveform generator than the PV waveform generator 150 used to bias the bias electrode 104. In some embodiments, the edge control electrode 115 may be biased by using a PV waveform generator 150 that is also used to bias the bias electrode 104 by splitting a portion of the power to the edge control electrode 115. In one configuration, a first PV waveform generator 150 of a first PV source assembly 196 is configured to bias the bias electrode 104 and a second PV waveform generator 150 of a second PV source assembly 197 is configured to bias the edge control electrode 115.

[0027]

[0031] A power feedline 157 electrically couples the output of the PV waveform generator 150 of the first PV source assembly 196 to the optional filter assembly 151 and the bias electrode 104. Although the power feedline 157 of the first PV power assembly 196 is described as being used to couple the PV waveform generator 150 to the bias electrode 104, the power feedline 158 of the second PV power assembly 197 coupling the PV waveform generator 150 to the edge control electrode 115 will include the same or similar components. The electrical conductors in the various parts of the power feedline 157 may be (a) a coaxial cable or combination such as a flexible coaxial cable coupled in series with a rigid coaxial cable, (b) an insulated high voltage corona resistant hook-up wire, (c) bare wire, (d) metal rod, (e) electrical connector, or (f) any combination of the electrical elements of (a)-(e). Optional filter assembly 151 includes one or more electrical elements configured to substantially prevent current generated by the output of RF generator 118 from flowing through power feed line 157 and damaging PV waveform generator 150. Optional filter assembly 151 acts as a high impedance (e.g., high Z) to the RF signal generated by RF generator 118, thus inhibiting current flow to PV waveform generator 150.

[0028]

[0032] The second PV source assembly 197 includes a clamp network 116 such that the bias applied to the edge control electrode 115 can be configured similarly to the bias applied to the bias electrode 104 by the clamp network 116 coupled in the first PV source assembly 196. Application of similarly configured PV waveforms and clamp voltages to the bias electrode 104 and edge control electrode 115 can help improve plasma uniformity across the substrate surface being processed, improving the results of the plasma treatment process.

[0029]

[0033] In some embodiments, the process chamber 100 further includes a quartz pipe 110 or collar that at least partially surrounds a portion of the substrate support assembly 136 to prevent the substrate support 105 and / or the support base 107 from contacting corrosive process gases or plasmas, cleaning gases or plasmas, or by-products thereof. Typically, the quartz pipe 110, the insulating plate 111, and the ground plate 112 are surrounded by a liner 108. In some embodiments, a plasma screen 109 is disposed between the cathode liner 108 and the sidewall 122 to prevent plasma from forming in the area beneath the plasma screen 109 between the liner 108 and the one or more sidewalls 122.

[0030] Examples of Radio Frequency (RF) Signal Generation Systems

[0034] Certain aspects of the present disclosure relate to techniques for hardware protection and industrial safety through the use of hardware switches in radio frequency (RF) plasma processing systems. For example, referring back to FIG. 1, the hardware switch 165 can be configured to decouple the RF generator 118 from the plasma assembly when a fault condition is detected to prevent damage to the RF generation system.

[0031]

[0035] An example of a type of fault condition includes RF reflected power, which can be monitored by elements in the system controller to protect against sudden impedance changes in the process chamber. If high reflected power or other faults are detected for a period of time (e.g., 5 seconds), a system safety interlock loop can be activated and an interlock signal (e.g., from the system controller 126) can be sent to the RF generator 118 to shut off the RF generator. However, high reflected power can still damage the RF power generator, especially when the RF generator is incorporated with a pulsed voltage generator. A hardware switch 165 provides a means to disconnect the RF generator 118 from the plasma assembly to prevent damage to the RF generation system.

[0032]

[0036] In some embodiments, the hardware switch 165 may be implemented as a vacuum interrupter. A vacuum interrupter is a switch that uses electrical contacts that are placed in a vacuum environment. In some embodiments, the switch is placed in an area surrounded by an electrical shield that can be connected to earth ground. Opening the vacuum interrupter switch facilitates a quick disconnection of the RF power provided by the RF generating system.

[0033]

[0037] The vacuum interrupter hardware switch provides various advantages. For example, the hardware switch can physically disconnect the main RF feed line for protection in addition to the software controlled switch that turns off the RF generator. The vacuum interrupter hardware switch provides additional protection to the system to prevent damage from overloads and short circuits. The hardware switch also improves safety when performing maintenance and diagnostics on the system. For example, during maintenance, the vacuum interrupter hardware switch 165 can be opened to prevent maintenance personnel from being exposed to high voltages from the RF generator 118.

[0034]

[0038] Additionally, the hardware switch 165 may help to interrupt power in a safe, reliable, and reproducible manner. By separating the two switch electrodes (e.g., electrodes 302, 304 in FIG. 3) in a vacuum, the potential arcing point between the electrodes upon disconnection is well defined within the switch itself, which helps to avoid potential damage elsewhere in the system. In other words, an arc caused by the opening of the hardware switch may desirably form between the electrodes of the switch and the vacuum enclosure of the vacuum interrupter, or between the electrodes of the switch, but between the electrodes and other components. Thus, the vacuum interrupter provides a well defined arcing point in the vacuum enclosure, which helps to avoid potential damage to components in the RF generating system and other systems within the plasma processing chamber. Also, under normal processing conditions, the switch can carry the full load of RF current. In some examples, the vacuum interrupter can be adequately sealed in a ceramic enclosure at pressures below 1 Pa, which provides improved dielectric strength, fast dielectric recovery rates, and improved reliability.

[0035]

[0039] In addition, the vacuum interrupter hardware switch provides better insulation strength and fast recovery speed, improving arc extinguishing capability. The reliable and maintenance-free hardware switch has a long service life and is suitable for repeated operation.

[0036]

[0040] As another advantage, the switch logic and operation can be user defined and tied into the system's interlock loops. For example, if a fault or unexpected voltage, current or impedance change is detected, the hardware switch can shut off RF power within fast time scales (e.g., within milliseconds).

[0037]

[0041] FIG. 2 illustrates an RF generation system 200 according to certain embodiments of the present disclosure. For ease of discussion, components of the first PV source assembly 196 and the second PV source assembly 197 are omitted from FIG. 2. The RF generation system 200 may form part of the plasma generator assembly 163 illustrated in FIG. 1. Although a single RF generator 118 is illustrated in FIG. 1, power from multiple RF generators may be combined in some cases. For example, as illustrated in FIG. 2, the RF generation system 200 includes RF generators 202, 204. The outputs of the RF generators 202, 204 may be coupled to RF impedance matching networks 206, 208 (e.g., corresponding to the RF matching circuit 162). Thus, the RF filters 210, 211 form part of the filter assembly 161 (FIG. 1), and the RF matching networks 206, 208 form part of the RF matching circuit 162 (FIG. 1). The RF impedance matching network is an electrical circuit used between the RF generator and the plasma reactor to improve power delivery efficiency. At the adjusted matching point, maximum power is delivered to the plasma load and nearly zero power is reflected back to the RF generating system. As shown, RF filters 210, 211 may be coupled to the outputs of the RF matching networks 206, 208. To combine the different RF powers from the RF generators 202, 204 to the cathode in the chamber assembly, RF filters 210, 211 may be used between the RF matching circuits and the chamber assembly. The RF filters 210, 211 may be designed to allow passage of RF power in a selected frequency range (e.g., including the frequencies associated with each of the RF generators 202, 204) and to isolate the RF generators from each other. As shown, the outputs of the RF filters 210, 211 are coupled to a common node 213 to combine the RF powers from the RF generators.

[0038]

[0042] As described, to mitigate potential hazards and damage to the system, a hardware switch 165 may be included on the main feedline (e.g., RF power feedline 167). As shown, the hardware switch 165 is located at the output of the RF filters 210, 211. An actuator 214 may be used to operate a movable portion of the hardware switch 165 that can selectively couple and decouple RF power by using commands from a controller 218. In some embodiments, as shown in FIG. 2, the hardware switch 165 and main feedline are coupled between one or more electrodes disposed within the substrate support assembly 136 and one or both of the RF generators 202, 204.

[0039]

[0043] As shown, the RF generation system 200 can include a system controller 218 that forms part of the system controller 126. If a fault is captured by the system controller 218, an interlock signal can be sent to both the RF generators 202, 204 and the actuator 214. The actuator 214 can then operate to open the hardware switch 165, which will cause the RF generators 202, 204 to begin turning off. In some configurations, it may be desirable to provide more hardware switches at the output of the RF generators, the output of the matching circuit, and / or elsewhere on the RF feedline to increase reliability.

[0040]

[0044] FIG. 3 illustrates an implementation of the hardware switch 165 using a vacuum interrupter. In some embodiments, the vacuum interrupter functions as a breaker that includes at least one fixed electrode (e.g., electrode 302), a movable electrode (e.g., electrode 304), and a ceramic container used as a vacuum housing 308 and an outer insulator (e.g., metal enclosure 310). The electrode 302 and the movable electrode 304 may be formed from a high melting point metal or other useful material that can repeatedly form reliable electrical contact. The vacuum interrupter is placed in an enclosed area 305 within the metal enclosure 310, which is connected to a common ground as an RF current return path. The metal enclosure 310 serves to safely isolate the RF power supply components from the user, minimize additional RF generated electromagnetic interference, and control stray capacitance formed by adding the hardware switch 165 in the processing system. The movable electrode 304 can be pulled away or separated from the fixed electrode 302 by the actuator 214, which is controlled by the system controller 218 described with respect to FIG. 2. Upon receiving a safety interlock signal from the system controller 218, the actuator decouples (e.g., pulls apart) the two mating electrodes and interrupts the supply of RF power. The actuator 214 can be operated by either a magnetic or pneumatic mechanism. Pneumatic actuators can be used inside or outside the RF environment. Magnetic actuators can be located outside the RF environment to avoid RF interference with the actuator solenoid. The outer metal enclosure provides a return path for the RF current and is connected to the chamber common ground. The RF current flows through the electrodes to the process chamber and back to the inner surface of the metal enclosure.

[0041]

[0045] In some embodiments, detecting a fault condition may include detecting a sudden change in voltage (e.g., a sudden change in voltage at common node 213) or current to or from the process chamber 100. In some embodiments, a sudden change in impedance associated with the RF matching circuit may indicate a fault condition, as described in more detail in FIG.

[0042]

[0046] 4 illustrates an exemplary RF matching circuit 400 (e.g., corresponding to RF matching network 206 or 208). As illustrated, the RF matching circuit 400 includes a series inductance element LSER, an adjustable series capacitance element CSER, and an adjustable shunt capacitance element CSHUNT that can be controlled by an input from the controller 218. In some embodiments, the RF matching circuit 400 may alternatively be formed by using other circuit element configurations, such as, for example, an L network, a pi network, or a transformer match circuit. The RF matching circuit 400 is generally configured to adjust the apparent load of the RF generator to 50Ω to reduce reflected power generated by the delivery of an RF signal from the RF generator and increase its power delivery efficiency. In some aspects, a fault condition may be detected by detecting a sudden change in capacitance of the adjustable shunt capacitance element CSHUNT (and / or the adjustable series capacitance element CSER).

[0043]

[0047] 5 is a process flow diagram illustrating a method 500 of plasma processing in accordance with certain embodiments of the present disclosure. The method 500 may be performed by an RF generating system, such as the RF generating system 200.

[0044]

[0048] At activity 502, an RF generation system generates (e.g., via RF generator 118 or RF generator 202) an RF signal that is provided to a bias electrode (e.g., bias electrode 104) of a plasma chamber (e.g., plasma chamber 100).

[0045]

[0049] In operation 504, the RF generation system detects a fault condition related to the operation of the plasma chamber. For example, detecting the fault condition may include detecting a change in voltage on an RF feed line (e.g., RF power supply line 167) between the RF generator and the plasma chamber, or detecting a change in current between the RF generator and the plasma chamber. In some embodiments, detecting the fault condition may include detecting a change in impedance (e.g., a change in capacitance of CSchunt or CSER) related to an RF matching network (e.g., RF matching network 206) coupled between the RF generator and the plasma chamber. In some embodiments, detecting the fault condition may include detecting an opening of a cover of the process chamber 100, an emergency stop button, and / or other commands sent from the controller 218.

[0046]

[0050] In operation 506, the RF generation system may decouple the RF generator from the plasma chamber (e.g., via a hardware switch 165 implemented as a vacuum interrupter) based on the detection of the fault condition. For example, decoupling the RF generator may include opening a vacuum interrupter hardware switch based on the detection of the fault condition. In some aspects, the RF generation system and / or the controller 218 also turn off the RF generator based on the detection of the fault condition.

[0047]

[0051] In some embodiments, the RF generator is decoupled from the plasma chamber by controlling an actuator (e.g., actuator 214) of a vacuum interrupter. The vacuum interrupter may include a first electrode (e.g., electrode 302) disposed within a vacuum housing (e.g., vacuum housing 308) and a second electrode (e.g., electrode 304) disposed within the vacuum housing. In some embodiments, decoupling the RF generator from the plasma chamber includes decoupling the first electrode from the second electrode based on detection of a fault condition. In some embodiments, the vacuum interrupter further includes a metal enclosure (e.g., metal enclosure 310) at least partially around the vacuum housing, the metal enclosure being coupled to ground.

[0048]

[0052] In some embodiments, the RF generation system can filter (e.g., via filter 210) an RF signal generated by the RF generator. The RF generation system can also generate another RF signal (e.g., via RF generator 204) and filter the other RF signal (e.g., via filter 211). The filtered RF signal and the other filtered RF signal can be combined and provided to the process chamber through a vacuum interrupter.

[0049]

[0053] The term "coupled" is used herein to refer to a direct or indirect coupling between two objects. For example, if object A is in physical contact with object B, and object B is in physical contact with object C, then objects A and C can still be considered to be coupled to each other even if they are not in direct physical contact with each other. For example, a first object can be coupled to a second object even if the first object is not in direct physical contact with the second object.

[0050]

[0054] No claim element is to be construed under 35 U.S.C. §112(f) unless the element is expressly recited using the phrase "means for," or, in the case of a method claim, the element is recited using the phrase "step for. In some embodiments, the means for generating an RF signal can include an RF generator, such as RF generator 118, RF generator 202, or RF generator 204, and the means for detecting can include a controller, such as controller 126 or controller 218.

[0051]

[0055] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, which scope is determined by the appended claims.

Claims

1. a first RF generator; and a vacuum interrupter including a first electrode disposed within a vacuum housing, a second electrode disposed within the vacuum housing, and a metal enclosure at least partially coupled to a ground and to a periphery of the vacuum housing; Including, The vacuum interrupter is configured to selectively decouple the first RF generator from a bias electrode of the plasma chamber by decoupling the first electrode from the second electrode based on detection of a fault condition related to operation of the plasma chamber.

2. Detecting the fault condition; 10. The RF generation system of claim 1, further comprising a controller configured to control the selective decoupling of the first RF generator from the bias electrode by the vacuum interrupter based on the detection.

3. The controller: opening a hardware switch of the vacuum interrupter upon said detection of the fault condition; The RF generation system of claim 2 , further configured to turn off the first RF generator based on the detection of the fault condition.

4. A first RF generator; a vacuum interrupter configured to selectively decouple the first RF generator from a bias electrode of a plasma chamber based on detection of a fault condition related to operation of the plasma chamber; a controller configured to detect the fault condition and, based on the detection, control the selective decoupling of the first RF generator from the bias electrode by the vacuum interrupter; an actuator configured to control the vacuum interrupter; The controller is configured to control the vacuum interrupter via the actuator.

5. The RF generating system of claim 4 , wherein the actuator comprises a pneumatic actuator or a magnetic actuator.

6. The controller: the voltage on an RF feed line between the first RF generator and the bias electrode of the plasma chamber; or A current between the first RF generator and the plasma chamber.

3. The RF generating system of claim 2 configured to detect the fault condition based on at least one of:

7. 3. The RF generation system of claim 2, further comprising an RF matching network coupled between the first RF generator and the plasma chamber, the controller being configured to detect the fault condition by detecting a change in impedance associated with the RF matching network.

8. a first filter coupled between the first RF generator and the vacuum interrupter; A second RF generator; and a second filter coupled between the second RF generator and the vacuum interrupter. The RF generating system of claim 1 further comprising:

9. an RF matching circuit coupled between the first RF generator and the first filter; and another RF matching circuit coupled between the second RF generator and the second filter; 9. The RF generating system of claim 8, further comprising:

10. 1. A plasma processing method, comprising: generating an RF signal via a first RF generator that is provided to a bias electrode of a plasma chamber; detecting a fault condition relating to operation of the plasma chamber; decoupling the first RF generator from the bias electrode of the plasma chamber via a vacuum interrupter based on the detection of the fault condition. Including, The vacuum circuit breaker comprises: a first electrode disposed within the vacuum housing; a second electrode disposed within the vacuum housing; a metal enclosure at least partially coupled to a ground point and to a periphery of the vacuum housing; The method of claim 1, wherein decoupling the first RF generator from the bias electrode of the plasma chamber comprises decoupling the first electrode from the second electrode based on the detection of the fault condition.

11. decoupling the first RF generator includes opening a hardware switch of the vacuum interrupter based on the detection of the fault condition; The method of claim 10 , further comprising turning off the first RF generator based on the detection of the fault condition.

12. A plasma processing method comprising the steps of: generating an RF signal via a first RF generator that is provided to a bias electrode of a plasma chamber; detecting a fault condition relating to operation of the plasma chamber; decoupling the first RF generator from the bias electrode of the plasma chamber via a vacuum interrupter based on the detection of the fault condition. Including, The method of claim 1, wherein the first RF generator is decoupled from the bias electrode of the plasma chamber by controlling an actuator of the vacuum interrupter.

13. detecting the fault condition, detecting a change in voltage in an RF feed line between the first RF generator and the plasma chamber; or detecting a change in current between the first RF generator and the bias electrode of the plasma chamber; The method of claim 10, comprising:

14. 11. The method of claim 10, wherein detecting the fault condition comprises detecting a change in impedance associated with an RF match network coupled between the first RF generator and the bias electrode of the plasma chamber.

15. filtering the RF signal generated by the first RF generator; generating another RF signal via a second RF generator; and filtering said another RF signal; 11. The method of claim 10, further comprising: wherein the filtered RF signal and the filtered separate RF signal are combined and provided to the bias electrode of the plasma chamber through the vacuum interrupter.

16. means for generating an RF signal that is supplied to a bias electrode of the plasma chamber; means for detecting a fault condition relating to operation of the plasma chamber; a vacuum interrupter including a first electrode disposed within a vacuum housing, a second electrode disposed within the vacuum housing, and a metal enclosure at least partially coupled to a ground and to a periphery of the vacuum housing; Including, the vacuum interrupter is configured to decouple a first RF generator from the plasma chamber by decoupling the first electrode from the second electrode based on the detection of the fault condition.

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