A controller for a matching unit of a plasma processing system

Abstract

A matching unit controller is provided for operation in conjunction with a matching unit of a plasma processor. The controller has a master controller application and acts as a local master controller within the matching unit. The controller collects data from input and output sensors and feeds this data to a smart algorithm. The output from the algorithm is used to set the position of the matching unit capacitor. The controller also has a slave controller application for communication with a master controller of the plasma processor.

Description

[Technical Field]

[0001] The present invention generally relates to a control system for an RF matching network (unit) used in plasma processing machines and other RF power delivery applications. [Previous Technology]

[0002] Plasma processing is widely used in the manufacture of semiconductor devices, solar cells, flat panel displays, and certain medical devices (to name just a few). One of the most common methods for stimulating plasma processes is to deliver electrical energy via RF (radio frequency) into a processing chamber containing a mixture of process gases. Some of the parent gas atoms or molecules are ionized, thus generating sufficient free electrons and particles to form plasma (also known as the fourth state of matter). The plasma state produces highly reactive ionic matter that falls onto any workpiece introduced into the plasma chamber. This bombardment of ionic matter modifies the workpiece surface to produce a predetermined structure, feature, or surface property.

[0003] In a typical RF plasma process, RF power is coupled via electrodes or an antenna to a gas mixture within a chamber to excite the plasma state. RF power is most commonly delivered at 13.56 MHz, but frequencies ranging from tens of kilohertz to hundreds of megahertz are also frequently seen. The RF generator delivers power to the processing chamber via a transmission line. Matching the characteristic impedance of the transmission line to the generator's output impedance, typically 50 ohms, optimizes power coupling. Ideally, the chamber impedance should also be 50 ohms to avoid impedance mismatch and power reflection back to the generator. Unfortunately, plasma chambers are unlikely to have a characteristic impedance of 50 ohms at all frequencies and under all plasma conditions. Therefore, an intermediate circuit is used to impedance match the RF generator, transmission line, and plasma chamber. This intermediate circuit, with adjustable impedance, is commonly referred to as an RF impedance matching network.

[0004] The RF matching network transforms the RF impedance of the plasma chamber to 50 ohms to maximize power delivery from the generator. In other words, when measured in the plane where the transmission lines are connected, the combination of the matching network (circuit) and the plasma chamber is 50 ohms. A typical RF matching network includes an input power sensor, variable capacitors, inductors, and a controller circuit on which an automatic matching adjustment algorithm can be programmed in a microprocessor or microcontroller. The topology of the matching network (circuit) and the values / sizes of the variable capacitors / inductors that make up the RF matching network are determined by the power delivery requirements, operating frequency, and impedance range of the plasma processing chamber.

[0005] Commonly used input sensors in RF matching network applications are directional couplers and phase / magnetic field detectors. VI (voltage and current) probes or sensors are less common. Directional couplers measure the forward and reflected power at the matching input. Plasma / magnetic field detectors monitor the magnitude and phase of the impedance of the matching network's cavity. Data from the input sensors is fed to a controller, where algorithms are used to adjust the variable capacitor value to minimize reflected RF power in the case of directional couplers, or to make the impedance magnitude and phase 50 ohms and zero degrees, respectively, in the case of phase / magnetic field detectors. This is effective for simpler continuous RF processes. For more complex semiconductor manufacturing processes, where RF power is pulsed and the RF is dynamic, more advanced sensors, such as VI probes, are needed at the input and output sides of the matching network. Advanced VI probes monitor the magnitude (and harmonics) of RF voltage and current and their phase shifts. Therefore, these probes can accurately measure complex impedance at matched 50 ohms (input side) and non-50 ohms (output side) during pulse application and in the presence of dynamic frequency modulation.

[0006] The advantage of having a precise output sensor in a matching network is that it allows for direct measurement of chamber impedance. This provides additional data points for faster impedance matching. It also reduces reliance on preset capacitor locations, where capacitors need to be near the matching point to avoid "getting lost" during adjustment. The controller used in a typical matching network runs a control algorithm. This control algorithm is proprietary to the matching network manufacturer and cannot be configured by the user. This limits the matching network's adaptability to new processes, which is a key requirement for smart manufacturing processes (explained in more detail below). Therefore, a smart matching network controller used in conjunction with precise input and output VI probes is highly desirable.

[0007] As nanotechnology devices shrink in size and / or become more complex, the processes used to manufacture these devices also become more complex. Specifically, semiconductor integrated circuit design has become more mainstream, with many technology giants preferring to design their own devices to meet their specific needs. However, semiconductor manufacturing has not been as mainstream due to the enormous costs and complexity involved. This has forced semiconductor device manufacturers to make their production lines smarter to handle the diverse range of semiconductor devices to be manufactured. Smart sensors, such as input and output VI probes in matching networks, are key to smarter, more adaptable manufacturing processes.

[0008] Smart manufacturing is generally defined as highly adaptable computer-integrated manufacturing, which allows for rapid modifications to manufacturing processes. Smart manufacturing relies on smart sensors that automatically collect and analyze data, and smart controllers that make intelligent decisions based on this sensor data to optimize the performance of production machines. Industrial IoT (Internet of Things) connectivity solutions, typically deployed at the factory level, transmit data from sensors and machines to the cloud or factory network. Industrial IoT technology enables data to flow within the factory and provides the ability to monitor and manage processes remotely, thus allowing for rapid and real-time changes to production schedules as needed.

[0009] A key consideration in smart factories is the volume of data generated by smart sensors and machines. Edge analytics is a term used to describe the collection and analysis of data performed on or near smart sensors, rather than waiting for the data to be sent back to a centralized database. Running data at the source, at the edge of the factory network, through analytics algorithms allows companies to set parameters regarding which information is worth storing in the database for later use and which data can be discarded. Analyzing data as it is generated also reduces latency in the decision-making process. For example, if a local controller analyzes input and output sensor data from a matched network, rules built into the analytics algorithm to interpret the data at the network edge can automatically adjust variable capacitors to optimal positions. The reduced dataset can then be sent to a centralized location for storage. Algorithm rules can be quickly modified on the factory network, even if the network has speed requirements that are slower than the actual data processing speed.

[0010] Key aspects of smart factory implementation schemes include the speed, reliability, and suitability of network connections. By definition, factory automation control systems are "real-time systems." Control machines typically require very low latency. Messages transmitted over the network should have associated priorities; for example, emergency stop messages should not be delayed by large backup data streams. Real-time messages should be prioritized. In conventional Ethernet networks, there is no prioritization protocol that treats all data equally. Despite being inexpensive and fast, Ethernet is not easily adapted for interconnecting control systems. The main problem lies in the determinism or timing accuracy required for real-time control.

[0011] Therefore, there is a need for a controller for the matching unit that overcomes the shortcomings of the prior art. [Summary of the Invention]

[0012] The present invention relates to a controller for a matching unit in a plasma processing system, the controller being configured to: receive impedance data from the matching unit regarding an RF generator in the system (measured from the RF generator side of the system); receive impedance data from the matching unit regarding a chamber in the system; process the impedance data using an algorithm to determine a target impedance of the matching unit so that the impedance of the chamber matches the impedance of the generator; adjust the capacitance of a variable capacitor in the matching unit to achieve the target impedance, wherein the controller is further configured to simultaneously: act as a master controller of the matching unit when communicating with the matching unit, and act as a slave controller of the matching unit when communicating with a master controller of the plasma processing system.

[0013] The controller can be further configured to communicate with the matching and plasma processing system via a network based on at least one network protocol.

[0014] Wherein, the impedance data is received and processed and the capacitors are adjusted for each step in a multi-step plasma process, and the controller is configured to receive an algorithm during each step of the plasma process and to use the received algorithm for a subsequent step of the plasma process.

[0015] Depending on the circumstances, the controller may be further configured to receive an algorithm via the network when performing the reception and processing of the impedance data and the adjustment of any of the capacitors, and to store the received algorithm for later use.

[0016] The controller may be further configured to receive an algorithm from one of the master controllers of the plasma processing system when acting as the slave controller of the matching unit, and simultaneously act as the master controller of the matching unit.

[0017] The controller can be further configured to store a high-resolution map of one of the impedance matching ranges, wherein the map is used to find the target impedance based on the impedance data from the output sensor.

[0018] The controller can be further configured to process the impedance data of the chamber of the system, using the algorithm to find the conjugate impedance on the high-resolution map and adjust the capacitance of the variable capacitors to achieve the conjugate impedance.

[0019] The controller can be further configured to apply a fine-tuning step after the capacitors have been adjusted to achieve the conjugate impedance, the fine-tuning step further adjusting the capacitance of the capacitors to maximize power delivery.

[0020] Impedance data about the RF generator of the system can be received from one of the input sensors of the matching unit.

[0021] Depending on the circumstances, the input sensor monitors the magnitude of RF voltage and current, their harmonics, and the phase shift between them.

[0022] Impedance data about one of the chambers of the system can be received from the output sensor of one of the matching units.

[0023] Depending on the circumstances, the input sensor and the output sensor monitor the magnitudes of RF voltage and current, their harmonics and phase shifts between them.

[0024] The controller can be further configured to interface with a computer via a communication port different from one used for communicating with the plasma processing system.

[0025] Depending on the circumstances, the controller may be further configured to receive an algorithm via the interface, store the received algorithm, and use the algorithm to determine the target impedance.

[0026] The teachings of the present invention are also directed to the matching unit including the above-described controller.

Implementation Method

[0028] The present invention provides a controller 100 for controlling a radio frequency matching network (unit) 101, the controller being referred to below as a matching controller. In one embodiment, the matching controller is installed inside the matching network housing.

[0029] The matching controller 100 according to the teachings of the present invention relies on the use of a standardized communication protocol. EtherCAT has been found to be suitable. This protocol was developed by Beckhoff Automation; Beckhoff Automation is a major manufacturer of PLCs (Programmable Logic Controllers) used in industrial automation and real-time control systems. EtherCAT is a real-time industrial Ethernet technology. The EtherCAT protocol is suitable for real-time applications in industrial automation. Two key focuses during the development of EtherCAT were a short cycle time (or latency) of ≤ 100 µs and low jitter for precise synchronization of ≤ 1 µs. The semiconductor industry uses EtherCAT as an automation standard, and EtherCAT device profiles and standards are now available for semiconductor industry-specific devices, including RF generators and matching networks.

[0030] The EtherCAT "master" sends a message that is transmitted through each device or node on the EtherCAT network. Each EtherCAT "slave" device on the network reads the data sent to it and inserts its data into a message frame. The last node detects an open port and sends the message back to the EtherCAT master using full-duplex capability. The EtherCAT master is the only node that is allowed to actively send EtherCAT frames. All other nodes (slaves) simply forward frames downstream, thereby preventing unpredictable delays and ensuring real-time capability. This complicates the EtherCAT-based matching controller 100. If the input sensor 102, output sensor 103, and variable capacitor 104 all use the EtherCAT protocol, the local matching network controller 100 should act as the EtherCAT master for these sensors and capacitors. However, a plasma processor (of which the matching network is part) may have an EtherCAT master controller to control all EtherCAT devices on the machine, including the matching unit 101. Due to the EtherCat architecture, it is impossible to have two master controllers.

[0031] When data is read from RF sensors 102 and 103 and used to control the variable capacitor 104 or the interlock switch, the matching controller 100 according to the present invention acts as an EtherCat master 105. The matching controller 100 acts as an EtherCat slave 106 for communicating with the EtherCat master controller 107 of the plasma processor. For a variety of reasons, it is better to confine the matching controller 100 to the matching network 101 / near it than to control the matching network 101 from a distance (e.g., from the plant network).

[0032] In EtherCat master mode 105, the confinement of the matching controller 100 within the matching network housing allows it to operate independently of the factory network at various speeds. This achieves lower latency when operating near the edge of the factory network where sensor data is generated. Intelligent algorithms can be deployed to the matching controller CPU 108 and modified in real-time via EtherCat or other provided protocols. Data from sensors 102, 103 is transmitted via intelligent analysis algorithms to quickly determine plasma impedance and accordingly adjust the position of capacitor 104 to optimize matching performance. The matching controller 100 can receive algorithms during plasma process steps while reading data from RF sensors 102, 103 and using that data to control variable capacitors. The received algorithms can be used in subsequent steps of the same plasma process or in different plasma processes. Receiving and processing impedance data and adjusting capacitors occur continuously on a millisecond timescale. Therefore, adjustment is a continuous process during each process step. New algorithms can be sent / received at any time, and these new algorithms can be used within existing steps or in subsequent or any later steps. The control system is scalable to handle multiple sensors and devices, such as capacitors and interlock switches, as needed.

[0033] Figure 2 illustrates a matching controller 100 that exhibits both master and slave capabilities to enable a multi-level control architecture. As previously described, the plasma processor has a master controller for controlling all (slave) devices 201 on the machine, including the matching unit 101. The slave devices 202 may be the previously mentioned RF sensors 102, 103, variable capacitor 104, or other slave devices of the matching unit 101.

[0034] A key feature of this invention is that end users can access and modify the algorithm on the controller 100. When the first algorithm is used in the first step of the plasma process, the matching controller 100 can receive a second algorithm and use that algorithm in the second (or subsequent) step of the plasma process. Existing matching networks do not have this capability, where only the engineering team of the matching network vendor can modify the matching algorithm. This is an important feature of plasma process development, where rapid prototyping and testing of novel RF matching schemes and algorithms can significantly reduce process development time for plasma process equipment manufacturers.

[0035] In one embodiment, the RF impedance matching network (unit) is a dual-frequency matching network integrated with a configurable, automatically adjusting matching controller. The plasma (or tool) host computer communicates with the matching controller via an EtherCat network. Note that the matching controller is not limited to an EtherCat connection, and those skilled in the art will understand that any of many other protocols can be used with minor modifications. Some suitable alternative protocols are outlined in the table below. It should also be understood that a mixture of protocols can be used because the motor (for capacitor 104) requires very little data, while the sensor will require high bandwidth. Regardless of the protocol chosen, controller 100 can be considered a slave device 106 to plasma tool master controller 107. protocol media Electrical noise immunity speed connect Integration EtherCat 100T Ethernet good high Daisy chain / On-site busbar Easy to follow standards Ethernet / IP 100T Ethernet good high Bus (requires a network router) Easy to follow standards ModBus / TCP 100T Ethernet good High / Medium Bus (requires a network router) Easy to follow standards TCP slot 100T Ethernet good Highly likely Bus (requires a network router) Each device will have a proprietary agreement. Internet services 100T Ethernet good Medium / Low Bus (requires a network router) Easy to follow standards SPI 3 / 4 line Low High / Medium Point-to-point (full-duplex) Each device will have a proprietary agreement. RS232 3 lines medium medium peer to peer Each device will have a proprietary agreement. RS485 5 lines good medium peer-to-peer or daisy chain Each device will have a proprietary agreement. CAN 5 lines good Low Daisy chain Easy to follow standards ModBus 5 lines good Low Daisy chain Easy to follow standards Device Network 5 lines good Low Daisy chain Easy to follow standards

[0036] Dual-frequency matching networks are commonly used in the industry, where two radio frequencies (from two independent RF sources) are fed into two matching networks before being combined into a single line at the output. For this topology, the controller can access two input sensors 102 (to measure impedance at each frequency at the input) and one output sensor 103 to measure the combined dual-frequency output impedance. The matching network may have four or more motorized tuning capacitors 104, which also communicate directly with the matching controller. In one configuration, the matching controller 100 is an EtherCat master 105 that communicates with the input sensors 102 and the output sensors 103 (VI sensors) to read RF data at each drive frequency, including RF impedance, and uses this RF data to calculate the optimal position of the capacitors 104. The position of the capacitors 104 is moved accordingly using a motor interface protocol 109.

[0037] Figure 1 illustrates an embodiment of an RF matching controller design according to the teachings of the present invention. In this exemplary embodiment, the matching controller 100 is located within the wall of the matching network (unit) 101 housing. It may also be located near the matching network rather than inside the housing. Other hardware located inside the matching network 101 includes an RF input sensor 102, an RF output sensor 103, a motorized capacitor 104, a status LED 110, a DC bias (Vdc) sensor 111, a temperature sensor 112, and an interlock switch 113. The RF matching controller housing encloses a computer or microcomputer 108 and its interface connectors.

[0038] In a preferred embodiment, the information hub is a Redis database 114, which is a shared memory variable storage device accessible to all applications. Redis (remote dictionary server) is a data structure storage device in memory and supports different types of abstract data structures, such as strings, lists, graphs, sets, etc. It is open-source software suitable for this application. However, many alternatives are available.

[0039] The EtherCat slave application 106 includes an EtherCat software stack that provides the application side of the EtherCat protocol. It supports the EtherCat slave controller (ESC) in updating its memory state and responding to requests for EtherCat CAN (CoE), EtherCat File (FoE), and other EtherCat services. The slave application 106 translates information stored in Redis into an EtherCat-compatible format and updates Redis with any new settings transmitted from the plasma tool EtherCat master 107.

[0040] The EtherCat main application 105 controls the local EtherCat network. It initializes RF sensors 102 and 103 and updates Redis 114 with sensor readings and the current motor position (variable capacitor settings). Any change in the calculated target motor position will trigger a change in the motor destination via the motor interface protocol 109.

[0041] The matching auto-adjustment application 115 reads sensor and motor position information from Redis 114, and if in auto-adjustment mode, updates the target position (corresponding to the target impedance) according to the selected auto-adjustment algorithm. As mentioned earlier, this algorithm can be customized by the user and updated in real time as needed. This update can be done via a Python development platform. That is, the slave device 106 can receive the Python algorithm 116 to update the auto-adjustment algorithm. This is an advantageous feature that enables rapid prototyping of the matching unit. Python is a high-level programming language with dynamic semantics, interpretation, and object-oriented architecture. Its built-in data structures make it an attractive tool for rapid application development. Python is a convenient scripting language commonly used to connect existing components together. Python interpreters and their extension libraries are freely available and distributed on all major platforms. Other scripting platforms can be used as alternatives to Python.

[0042] Many advanced plasma processes are driven by pulsed RF power, thus enabling plasma chemistry properties that cannot be obtained by plasma processes driven by continuous-wave RF power. Some processes can last for an hour or longer, with multiple consecutive processing steps. These steps can proceed uninterruptedly from one step to the next. Each step is carefully designed to progressively advance the feature being processed until completion. Therefore, each step involves some changes in process conditions. Pulsed power schemes can be complex, with multi-stage pulses providing better feature control. Pulse profile variations may involve changes in the number of pulse levels and / or the duration of each level. The overall pulse profile repetition frequency can also be changed. Matching controllers and matching networks are expected to function optimally at each step to ensure that maximum power is always delivered to the process. For the type of pulsed RF power scheme discussed, this almost certainly requires the use of different matching adjustment algorithms at each process step.

[0043] As we move towards smart manufacturing, with an anticipated increase in the variety of products flowing through production lines, it may be impossible to guarantee that processing steps will occur in the same order each time. For these reasons, it is necessary to re-evaluate known paradigms for adjusting matching unit algorithms before they are installed on processing equipment. A shift to a new paradigm is highly desirable, in which the main controller of the processing machine can issue commands in real time to the smart matching network to control the adjustment algorithm.

[0044] The matching network architecture shown in Figure 1 is designed to expose all matching hardware data to the factory EtherCat network. As shown, the matching controller can be installed locally in the matching box or reside entirely within the plasma tool master controller. The controller accessibility enabled by the network connection allows the plasma tool master controller to change the adjustment algorithm in real time using EtherCat File on Ether (FoE) or alternative protocols. As previously mentioned, this involves the matching controller receiving the algorithm via the network when performing either receiving and processing impedance data or adjusting capacitance. The received algorithm can be stored and used in the next step of the same plasma process, a subsequent step of the same process, or any step of different plasma processes. This is crucial for multi-step processes where the adjustment algorithm can be changed quickly and seamlessly as process steps transition from one step to another. Where the step sequence may change from time to time, the plasma tool master controller can select from the algorithm library and update the matching controller in real time.

[0045] Other inputs to the controller include EtherCat address selection, interlock switches, internal temperature sensors, and DC voltage sensors. Outputs from the controller will include status LEDs, RUN LEDs, and ERR LEDs for external EtherCat networks. These inputs interface with application 117 running on the CPU 108 of the controller 100, and the data is stored in Redis memory.

[0046] The controller can also be accessed via USB and / or RS232 118. When the matching controller is not on an EtherCat network, the matching controller can be configured using a user interface on a PC. This is important for offline testing and calibration when the controller (or the matching network / unit containing the controller) is not attached to the plasma processing tool / system. It should be understood that other interfaces or ports besides USB and RS232 can be used.

[0047] A typical (prior art) automatic adjustment matching network will have presets for capacitor position configuration. These presets are determined during the process development phase. The capacitor position (or value) is determined for standard process operation and stored in memory. Process drift, component degradation due to aging, and thermally induced drift due to power dissipation in the matching unit components cause changes in the optimal capacitor position. The fine-tuning algorithm monitors the power delivery drift and adjusts the capacitor position to compensate. For the device described herein, preset positions are not necessary. A high-resolution map of the impedance matching range can be stored in Redis memory. Output sensors (VI probes) accurately measure the process impedance. As a coarse-tuning step, the algorithm finds the conjugate impedance or corresponding impedance on the map and instructs the capacitor to go directly to this impedance position. A fine-tuning step is then applied to fine-tune the capacitor position to maximize the power delivery reported by the input sensors. This method allows for rapid adjustment of the matching unit when the process impedance changes.

[0048] Please note the following key features of the invention described herein: ● The local controller can operate independently of the factory master controller at multiple speeds. ● It can run local intelligent algorithms. ● It provides lower data latency at the network edge. ● It allows for customizable control algorithms that can be updated in real time. ● The controller can operate in both master and slave modes simultaneously. ● The control system is scalable, allowing seamless integration of multiple sensors / capacitors. ● It can be used as a Linux-based Ethercat master / slave control system and method.

[0049] It should also be noted that communication between various hardware components, including sensors and motors, within the mating network is typically specialized. Sensors may use local interfaces such as SPI or UART. Motors may be stepped via voltage level control and / or speed control, or via TTL signals, or using a local controller with UART / RS485. The use of standardized industrial network protocols means that components such as motors and sensors are interchangeable, thereby allowing manufacturers to directly integrate mating units into their tools.

[0050] Those skilled in the art will know that EtherCat networks typically have a single master controller and multiple slave devices. The teachings of this invention generate a local master controller that acts as a slave device when communicating with a higher-level master controller on the network. Thus, the controller operates as both a master and a slave. This achieves the control architecture shown in Figure 2, extending the well-known master / slave architecture to a new master / slave-master / slave architecture.

[0051] Another novel implementation of the matching unit control architecture is to integrate the controller 100 module into the plasma tool main controller to create a matching network that is fully remotely controlled. This results in the first locally controllerless matching unit. As mentioned earlier, the only drawback is that the speed is limited by the factory network speed. With improvements in network speed and reliability, especially with the rollout of 5G for future smart factories, fully remote control of the matching network will become even more attractive.

[0052] The device presented in the present teaching includes a matching unit controller that operates in conjunction with one or more RF input sensors and one or more RF output sensors. The controller has an EtherCAT master controller application and acts as a local EtherCAT master in the matching unit. The controller collects data from the input and output sensors and feeds the data to a smart algorithm. The output from the algorithm is used to set the position of the matching unit capacitor. The controller also has an EtherCAT slave controller application to communicate with the master controller of the plasma processor.

[0053] This document describes a controller that allows the user complete control over how the matching unit operates. The user can purchase a metal case, add readily available variable capacitors, inductors, sensors, etc., along with the matching unit controller (and sensors) described herein, and easily customize the matching unit to their own specifications. It can even incorporate intelligent algorithms. This enables rapid prototyping and faster process development.

[0054] The capacitance of the variable capacitor can be precisely adjusted by using a stepper motor.

[0055] The term "includes" as used in this specification will indicate the presence of the described feature, integer, step or component, but does not exclude the presence or addition of one or more other features, integers, steps, components or groups thereof. [Simplified Explanation of the Diagram]

[0027] The invention will be further described by way of example with reference to the accompanying drawings, in which: FIG1 shows a controller for a matching unit (network) of a plasma processor according to the teachings of the invention; and FIG2 shows the controller of FIG1 exhibiting both master and slave capabilities.

Claims

1. A controller for a matching unit in a plasma processing system, the controller being configured to: receive impedance data from the matching unit regarding an RF generator in the system; receive impedance data from the matching unit regarding a chamber in the system; process the impedance data according to an algorithm executed on the controller to determine a target impedance of the matching unit such that the impedance of the chamber matches the impedance of the RF generator; and adjust the capacitance of a variable capacitor of the matching unit to achieve the target impedance; wherein the controller is further configured to simultaneously: act as a master controller for the matching unit when communicating with the matching unit, and act as a slave controller for the matching unit when communicating with a master controller of the plasma processing system.

2. The controller of claim 1, wherein the controller is further configured to communicate with the matching unit and the main controller of the plasma processing system via a network based on at least one network protocol.

3. The controller of claim 2, wherein the controller is further configured to receive an algorithm via the network when performing any of receiving and processing the impedance data and adjusting the capacitances, and to store the received algorithm for later execution on the controller.

4. The controller of claim 3, wherein the receiving and processing of the impedance data and the adjustment of the capacitors are performed for each step in a multi-step plasma process, and the controller is configured to receive an algorithm during each step of the plasma process and execute the received algorithm on the controller for a subsequent step of the plasma process.

5. The controller as requested in item 3 or 4, wherein the controller is further configured to receive an algorithm from the master controller of the plasma processing system when acting as the slave controller for the matching unit, and simultaneously acting as the master controller for the matching unit.

6. The controller of claim 1, wherein the controller is further configured to store a high-resolution map of an impedance matching range, wherein the map is used to find the target impedance based on the impedance data from the output sensor.

7. The controller of claim 6, wherein the controller is further configured to process the impedance data of the chamber of the system, using the algorithm to find a conjugate impedance on the high-resolution map and adjust the capacitance of the variable capacitors to achieve the conjugate impedance.

8. The controller of claim 7, wherein the controller is further configured to apply a fine-tuning step after the variable capacitors have been adjusted to achieve the conjugate impedance, the fine-tuning step further adjusting the capacitance of the variable capacitors to maximize power delivery.

9. The controller of claim 1, wherein impedance data about the RF generator of the system is received from one of the input sensors of the matching unit.

10. The controller of claim 9, wherein the input sensor monitors the magnitudes of RF voltage and current, harmonics of the RF voltage and current, and phase shift between the RF voltage and current.

11. The controller of claim 1, wherein impedance data about a chamber of the system is received from an output sensor of one of the matching units.

12. The controller of claim 11, wherein the output sensor monitors the magnitude of the RF voltage and current, their harmonics and the phase shift therebetween.

13. The controller of claim 1, wherein the controller is further configured to interface with a computer via a communication port different from an interface used for communicating with the plasma processing system.

14. The controller of claim 13, wherein the controller is further configured to receive an algorithm via the interface, store the received algorithm and execute the algorithm to determine the target impedance.

15. A matching unit comprising a controller as requested in Request 1.

16. A controller for a matching unit in a plasma processing system, the controller being configured to: receive and execute an algorithm from a master controller of the plasma processing system; receive impedance data from the matching unit regarding an RF generator of the system; receive impedance data from the matching unit regarding a chamber of the system; process the impedance data according to the algorithm executed on the controller to determine a target impedance of the matching unit such that the impedance of the chamber matches the impedance of the RF generator; and adjust the capacitance of a variable capacitor of the matching unit to achieve the target impedance; wherein the controller is further configured to simultaneously: act as a master controller for the matching unit when communicating with the matching unit, and act as a slave controller for the matching unit when communicating with the master controller of the plasma processing system.

17. The controller of claim 16, wherein the controller is further configured to communicate with the matching unit and the main controller of the plasma processing system via a network based on at least one network protocol.

18. The controller of claim 17, wherein the controller is further configured to receive another algorithm via the network while performing any of receiving and processing the impedance data and adjusting the capacitances, and to store the received algorithm for later execution on the controller.

19. The controller of claim 18, wherein the receiving and processing of the impedance data and the adjustment of the capacitors are performed for each step in a multi-step plasma process, and the controller is configured to receive an algorithm during each step of the plasma process and execute the received algorithm on the controller for a subsequent step of the plasma process.

20. The controller of claim 18, wherein the controller for the matching unit is further configured to receive an algorithm from the master controller of the plasma processing system when acting as the slave controller for the matching unit, and simultaneously acting as the master controller for the matching unit.

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