Patent ID: 12230476

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

Preliminary note: the flowcharts and block diagrams in the following Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, some blocks in these flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

While the following disclosure generally refers to wafer plasma processing, implementations can comprise any substrate processing within a plasma chamber. In some instances, objects other than a substrate can be processed using the systems, methods, and apparatus herein disclosed. In other words, this disclosure applies to plasma processing of any object within a sub-atmospheric plasma processing chamber to effect a surface change, subsurface change, deposition or removal by physical or chemical means.

This disclosure may utilize plasma processing and substrate biasing techniques as disclosed in U.S. Pat. Nos. 9,287,092, 9,287,086, 9,435,029, 9,309,594, 9,767,988, 9,362,089, 9,105,447, 9,685,297, 9,210,790. The entirety of these applications is incorporated herein by reference. But it should be recognized that the reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter is conventional, routine, or forms part of the common general knowledge in the field of endeavor to which this specification relates.

For the purposes of this disclosure, source generators are those whose energy is primarily directed to generating and sustaining the plasma, while “bias supplies” are those whose energy is primarily directed to generating a surface potential for attracting ions and electrons from the plasma.

FIG.1shows an embodiment of a plasma processing system with many pieces of equipment coupled directly and indirectly to plasma chamber101, which contains a plasma102. The equipment comprises vacuum handling and gas delivery equipment106, bias generators108, a bias matching network110, bias measurement and diagnostics system111, source generators112, a source matching network113, source measurement and diagnostics system114, measurement and diagnostic equipment115, and a system controller116. The embodiment inFIG.1, and other embodiments described herein, are exemplary of the complexity of plasma processing systems, and the depiction of plasma systems herein helps to convey the interrelations of the equipment coupled to the plasma chamber101.

An example of the interrelations of the plasma processing equipment is the effect that modulating supplies (e.g., source generators112, bias generators108, and other modulating supplies discussed further herein) have on plasma properties (and control of the same). More specifically, modulating supplies can cause strong modulation of plasma properties such as the impedance presented by the plasma102to equipment of the plasma processing system100. Plasma modulation can also cause aliasing of measurements of plasma properties. Additional details about the effects of modulation of plasma properties are discussed further herein.

Shown inFIG.1is a plasma processing system100(e.g., deposition or etch system) containing a plasma chamber101within which a workpiece (e.g., a wafer)103is contained. A number of bias electrodes104are connected through the bias measurement and diagnostics system111to the bias match network110to which a number of bias generators108are connected. The bias electrodes104may be built into an electrostatic chuck to hold the workpiece103in place. This may involve integration of a high voltage DC power supply107into the system. In many applications, a single bias electrode104is used, but utilization of many bias electrodes104may be used to achieve a desired spatial control.

The bias generators108depicted inFIG.1may be lower frequency (e.g., 400 kHz to 13.56 MHz) RF generators that apply a sinusoidal waveform. Also shown is a set of source electrodes105connected to a number of source generators112through the source measurement and diagnostics system114and source matching network113. In many applications, power from a single source generator112is connected to one or multiple source electrodes105. The source generators112may be higher frequency RF generators (e.g. 13.56 MHz to 120 MHz). Vacuum maintenance, gas delivery and wafer handling equipment106may be implemented to complete the system and optionally additional measurement and diagnostic equipment115may be present (e.g. optical spectroscopy equipment).

The system controller116in the embodiment ofFIG.1controls the entire system through a system control bus117. The system control bus117can also be used to collect information from equipment of the plasma processing system. In addition to the system control bus117, there may be dedicated inter-system communication118which can be used, for example, to control the source matching network113from a source generator112or exchange information between subsystems without involving the system control bus117. There may also be a near-real-time communication link119between subsystems. This may take the form of a reference oscillator to phase lock different generators on the system, to provide waveform synchronization signals, arc detection signals, etc. Although a single source generator112is common, it is also common to have multiple source generators112and multiple bias generators108in order to achieve a desired plasma density and desired control over the distribution of ion energies. One or more of the source generators112and/or bias generators108can modulate the plasma properties and be considered as a modulating supply.

FIG.2shows an embodiment of a plasma processing system200where the source generators112are replaced by a remote plasma source205. As those of ordinary skill in the art will appreciate, the remote plasma source205may comprise an excitation source (e.g., an RF generator) and a plasma-generation chamber configured and disposed to produce a plasma that is provided to the plasma chamber101. Although the remote plasma source205is outside of the plasma chamber101, the remote plasma source205may be coupled to the plasma chamber101to form a contiguous volume with the plasma chamber101. Although unlikely in many embodiments, in some embodiments, the remote plasma source205may modulate plasma properties of the plasma102in the plasma chamber101. And if the remote plasma source205does modulate the plasma properties of the plasma102, the remote plasma source205and/or one or more of the bias generators108can be considered as a modulating supply.

FIG.3shows another embodiment of a plasma processing system where multiple bias generators are replaced by an integrated bias power delivery system308. Such integration can reduce system complexity and reduce duplication by, for example, using common DC power supplies for the RF generators, a common controller, auxiliary power supplies, measurement systems etc., but the output to the plasma chamber101is still a combination of a single or multiple RF frequencies and/or a DC signal. Many other variations exist such as, for example, using a source generator and integrated bias power delivery system or using integrated source and bias power delivery systems etc.

Referring next toFIG.4, shown is yet another embodiment of a plasma processing system that utilizes a bias supply408(instead of bias generators108) for an even tighter control over the distribution of ion energies. As shown, the bias supply408may apply a periodic waveform to several different electrodes104, or alternatively, a separate bias supply408may be coupled to each electrode104(not shown inFIG.4). As shown inFIG.5, it is contemplated that multiple bias supplies508may be utilized in connection with multiple generators109. It should be recognized that the embodiments described with reference toFIGS.1-5are not mutually exclusive and that various combinations of the depicted equipment may be employed.

Aspects of the present disclosure address challenges faced in the prior art by recognizing that traditional and even cutting edge components of plasma processing systems are still limited by their autonomous design. For example, bias supplies, source generators and match networks are often independently operated. This disclosure describes systems, methods, and apparatuses for integrating communication, measurement, and control amongst components of a power delivery system (also known as a power generation and delivery system). Some advantages of this approach comprise the ability to provide accurate power regulation over a wide dynamic range, faster power stabilization during transients, and decreased reflected power, for both pulsed and continuous wave (CW) power.

FIGS.6A to6Cillustrate aspects of power delivery systems that may be utilized in connection with the plasma processing systems described with reference toFIGS.1-5. The power delivery system600provides power (e.g., via inductive coupling and/or capacitive coupling) to a plasma102, where a match network604may minimize reflected power and/or achieve a stable plasma. A power output of the source generator112is provided to the match network604via a first transmission medium608and then on to the plasma102(of a plasma load606) via a second transmission medium610. A first sensor614and optional second618and third611sensors monitor electrical characteristics of the power by measuring one or more of voltage, current, phase, impedance, and power and pass (or relay) this information to a local controller. The local controller612resides in either the bias supply408, the source generator112, or the match network604(seeFIG.6C), or anywhere within the power delivery system600(seeFIG.6C), and manages communication between the bias supply408, source generator112, the match network604, and one or more of the sensors611,614,618. The local controller612can also manage communication between a user and any components of the power delivery system600. The local controller612can manage the power delivery system600so that rapidly-adjustable, constant, and accurate power is delivered to the plasma102according to one or more power delivery requirements.

The one or more sensors611,614,618monitor the power for the local controller612. In particular, the first sensor614can monitor a power output of the source generator112as well as an impedance seen by the source generator112. The local controller612analyzes measurements provided by the first sensor614(and optionally also the second sensor618) in light of the power delivery requirements. It can determine operating parameters for the source generator112and match network604judged sufficient to meet the power delivery requirements, and can instruct (or relay instructions to) the source generator112and the match network204to adjust internal parameters of those components in order to meet the power delivery requirements.

In addition, in some implementations, the local controller may be configured to operate with the functionality of the system controller116. It is also contemplated that the external controller616may be configured to operate with the functionality of the system controller116. Moreover, the functionality of the system controller116may be implemented across one or more local controllers612and one or more system controllers616. Thus, the aspects of integrating communication, measurement, and control amongst components of a power delivery system (described with reference toFIG.6AtoFIG.9may be utilized in connection with the embodiments and implementations described with reference toFIGS.1-5to control and synchronize equipment of plasma processing systems. The local controllers612and external controllers616,716,816,916may also provide additional functionality to augment the control methodologies described with reference toFIGS.1-5.

This unified power delivery system600, or the herein disclosed use of a local controller612in conjunction with the first sensor614(and optionally the second sensor618and third sensor611), has a number of advantages. First, by unifying control and operation of various components of the power delivery system600, novel power delivery methods are enabled, such as the ability to simultaneously tune the match network604and the source generator112or tune the match network604while pulsing or changing the waveform of the source generator112output. Second, this system and approach enables rapidly-adjustable, accurate, and consistent power delivery to the plasma102. The speed of the power delivery system600is particularly useful in dynamic power applications (e.g., pulsed source generator112output).

The ability to more rapidly adjust power delivery can in part be attributed to avoidance of delays that traditional systems see when sensors must first measure frequency before measuring impedance. The local controller612may provide the first sensor614with operating parameters of the generator, such as frequency, so that the first sensor614need not measure frequency before beginning to sample for impedance. Earlier sampling means that impedance can be determined faster than in the art. The local controller612can also provide the first sensor614with an indication of the start of pulsing or a change in a power waveform, thus preventing the first sensor614from having to detect such a change before sampling begins. This also enables the first sensor614to begin measuring impedance sooner than sensors in the art.

The power delivery system600also improves the accuracy of power delivery. For example, when multiple sensors are used to measure power and impedance each sensor has an error function associated with that sensor resulting from calibrations that are made to each sensor. By using a single sensor614to measure power and impedance, only a single calibration is performed, and therefore less error is introduced.

In addition, having a greater number of sampling points can improve impedance measurements. In the art, sampling typically can only begin after a pulse or change in the generator waveform has been detected, whereas here, the local controller612may indicate to the first sensor614a start of a pulse or change in the source generator112waveform before or when the pulse or waveform change occurs. As such, the first sensor614can begin sampling earlier than is possible in the art, thus enabling more accurate impedance measurements.

Moreover, a measure of impedance depends on the frequency of the signal being measured; thus, errors in measuring frequency translate to errors in the impedance that is measured. Prior art impedance measurements are often made after a sensor in the match network measures frequency, thus introducing unnecessary error. Alternatively, when using a broadband sensor, error is introduced by analog variation in the broadband sensor as a function of frequency. By making the first sensor614aware of the frequency that the source generator112is producing, rather than requiring the first sensor614to measure the frequency at the match network, the first sensor614sees less error in impedance measurements than sensors in the prior art. Also, because the first sensor614does not have to measure frequency, it can take more samples, and a larger sample size improves accuracy.

In addition, because every component (e.g., source generator112, first sensor614, match network604, optional second sensor618) in a power delivery system is different, operating parameters of a power delivery system are preferably adjusted when different components are substituted. Traditional power supplies do not account for variations between components. In contrast, the local controller612is aware of the various components of the power delivery system600and adjusts its instructions to the source generator112and the match network604accordingly.

Component variations can be taken into account by identification of the components to the local controller612. For instance, the bias supply408, source generator112, and/or match network604can identify themselves to the local controller612via brand, model, serial number or other identifying information. Also, they can provide operating characteristics such as status, set point (e.g., power level, frequency, etc), repetition period T, and configuration, to name a few. This can be done via the RF engine613and the impedance control system615, respectively. The first and second sensors614,618can also identify themselves to the local controller612. Authentication may take place via an authentication algorithm. As such, in one embodiment, only specific types or brands of bias supply408, source generator112, and match network604are operable when connected via the transmission medium608. The local controller612can also query the bias supply, source generator112, the match network604, and the sensors614,618to determine their unit type, serial number, part number, or any other identifying information. With this knowledge, the local controller612can tailor instructions to the source generator112, bias supply408, and/or the match network604to account for variations in components, thus allowing the power delivery system600to provide more accurate and consistent power than is possible in the art.

The power delivery system600also improves the consistency (or quality) of power delivery because of the ability to measure both power and impedance. In part, consistency is improved via the greater accuracy described above (e.g., decreased error stack-up and earlier and more extensive sampling). Consistency is also improved, because, where the prior art had difficulty maintaining stability in multiple control loops of a power delivery system, the single controller612can control the multiple control loops and ensure stability and synchronization between the control loops.

A number of design aspects enable these advantages. For example, a single sensor614may be used to monitor both power output of the source generator112and an impedance seen by the source generator112. The first sensor614can measure voltage, current, phase, impedance, and power at an output of the source generator112. The first sensor614can be arranged at an output of the source generator112. The first sensor614can measure impedance seen by the source generator112in addition to power from the source generator112because of the ability to remotely measure impedance, a feature not possible in the art. Remote impedance measurements look at impedance at a location physically remote from the first sensor614(or the calibration point), for instance at a location some physical distance along the first transmission medium608from the first sensor614(e.g., at an input of the match network604).

Inaccuracies in traditional impedance measurements meant that remote monitoring of impedance was difficult if not impossible. The first sensor614may overcome these challenges for several reasons. For example, the first sensor614may have a more linear response with respect to increasing voltage standing wave ratio referenced to the calibration impedance than sensors in the art, and in addition, the first sensor614may more closely measure a phase of the source generator112output power.

Typically, sensors can be calibrated to operate optimally close to a center operating impedance (e.g., 50Ω), but due to their nonlinear response to impedance variations, as impedance moves away from the calibration impedance, sensor accuracy degrades rapidly. This inaccuracy for physically local measurements is amplified when making measurements over large physical distances. In contrast, in many implementations, the sensor614has a more linear response on the voltage standing wave ratio circle, which enables accurate impedance measurements at impedances far from the impedance calibration point and therefore at physically remote locations.

In addition, the first sensor614may be able to more closely measure a phase of the source generator112output than could prior generations of sensors. In particular, at high phase angles there is extreme sensitivity to phase angle measurement accuracy, and hence, high sensitivity in the resulting impedance and power measurements. Since the first sensor614can more accurately measure phase angle, it is better able to remotely measure impedance.

In an embodiment, the first sensor614is a directional coupler. A directional coupler can measure the scaled power of forward and reverse power as well as the phase difference between them. The directional coupler can then pass the scaled power and phase difference back to the local controller612. Scaled power is a voltage that the directional coupler provides to a measurement system that is proportional to an output voltage of the source generator112operating into its nominal load condition (e.g., 50Ω).

The advantages described above are secondly enabled by unified control and monitoring of the power delivery system600through a single local controller612. The local controller612can receive and analyze information from the source generator112, the match network604, the first sensor614, and the optional second sensor618. The local controller612may run one or more algorithms to analyze information received regarding the power delivery system600and determines procedures to take in order to ensure consistent power delivery to the plasma102. The local controller612can also issue instructions for other components in the power delivery system600, such as the source generator112and match network604, to carry out certain actions and procedures.

Since the local controller612monitors all measurements and distributes all control signals and instructions, many of an operator's responsibilities are alleviated and the speed with which the source generator112and match network604adjust to power and impedance fluctuations is enhanced. Such a configuration also simplifies the hardware requirements of the power delivery system600since fewer leads and signal lines are required. By minimizing the number of leads and signal lines, the source generator112and match network604can be controlled via smaller and less complex software and firmware.

Because the local controller612manages operation of both the source generator112and the match network604, simultaneous tuning of those components is possible. The local controller612can instruct an RF engine613of the source generator112to adjust an amplitude, carrier frequency, power frequency, pulse width, pulse duty cycle, or waveform of the source generator112power output. The local controller612can also instruct an impedance control system615of the match network604to adjust an impedance of the match network604, for instance by having a motor drive board adjust variable capacitors of the match network604.

Available tuning options can dictate how the local controller612manages the power delivery system600. Where the source generator112frequency is fixed, the local controller612can pass instructions to the match network604to adjust impedance. Where the source generator112frequency is variable, the local controller612can (1) pass instructions to the match network604to alter the impedance that the source generator112sees, (2) pass instructions to the source generator112to alter the power output frequency, or (3) pass instructions to the match network204to alter the impedance that the source generator112sees and to the source generator112to alter its power output frequency. Since the source generator112frequency is more quickly adjusted than the impedance of the match network604, instructing the source generator112to tune via frequency in addition to or instead of the match network204adjusting impedance, can be preferable where fast tuning is required. In other words, impedance matching can be performed via simultaneous tuning of the source generator112and the match network604.

More consistent and accurate power can be delivered when the local controller612takes into account information provided by the optional second sensor618. For instance, the optional second sensor618can provide data characterizing the power delivered to the plasma102; thus, enabling the local controller612to more accurately and consistently provide tuning instructions to the source generator112and the match network604. Measurements from the optional second sensor618can also be used for chamber matching—to improve consistent power delivery between chambers operating in parallel, but each with a different power delivery system. The local controller612can also use these measurements to improve wafer to wafer consistency, uniform processing across the wafer surface, end point detection (e.g., via monitoring light emissions from the plasma), and arc management. Although not illustrated, in some embodiments, the optional second sensor618can be arranged within the plasma chamber or in contact with the wafer.

In an embodiment, the power provided to the plasma102may be altered for various setpoints (e.g., from a first setpoint to a second setpoint). The match network604may not be able to adjust fast enough to maintain consistent power delivery to the plasma102when the source generator112switches between power setpoints. To overcome this challenge, a test run can be used to determine preferred set points for the match network604corresponding to each source generator112set point. The test run happens before a device, semiconductor, or any other object to be processed, is placed in the plasma chamber. The match network604and source generator112are then tuned for the various source generator112set points. Parameters that can be tuned comprise source generator112frequency, pulse width, and match network604impedance. This tuning is carried out without anything in the chamber so that slow tuning can take place without harming the device in the chamber. Parameters that are determined to be preferred for various source generator112set points can be stored in a memory. During actual plasma processing, the local controller612can issue instructions for the source generator112and the match network604to operate at the preferred parameters associated with the various setpoints. In this way, the match network604and source generator112do not have to tune during processing, but rather can quickly be set to the preferred parameters as determined in the test run.

The local controller612can also take into account the following non-limiting aspects characterizing the power delivery system600: component efficiency characteristics, control algorithm parameters, variable capacitor position in the match network604, diagnostics such as faults and warnings, component health metrics, component history logs, and component status requests.

The local controller612can also take into account non-electrical characteristics of the plasma102when managing operations of the source generator112and the match network604. For instance, the local controller612acan consider chamber pressure, gas chemistry in the chamber, ion energy of the plasma, light intensity of the plasma, spectral content of light emitted by the plasma, and plasma arcing to name a few non-limiting examples. In an embodiment, the optional second sensor618can monitor non-electrical characteristics of the plasma102or the plasma processing chamber (not illustrated), such as chamber pressure, gas chemistry in the chamber, ion energy of the plasma, light intensity of the plasma, spectral content of light emitted by the plasma, and plasma arcing, to name a few non-limiting examples.

As illustrated, the local controller612is the lone conduit for user interaction with the power delivery system600. In one embodiment, a user can interface with an external controller616, which is in communication with the local controller612. User control of the source generator112and match network604is made via the local controller612by way of the external controller616. However, one of skill in the art will recognize that user interaction with the power delivery system is not necessarily limited to the local controller612.

The first sensor614can optionally be implemented along with an optional second sensor618(or load sensor). The optional second sensor618can be arranged at an output of the match network604(618a) or somewhere between and including the match network204and the plasma102(618b). The optional second sensor618is configured to characterize the power delivered to the plasma102and can measure voltage, current, phase, impedance, or power at the output of the match network604or anywhere between the match network604and the plasma102. In an embodiment, the optional second sensor618can be coupled to the plasma102and can be arranged within the plasma processing chamber or coupled to a wafer during processing.

The local controller612can manage communications between the source generator112(in particular, the RF engine613), the first sensor614, the match network604(in particular, the impedance control system615), and the optional second sensor618, between itself and these components, and between these components and a user (e.g., via the external controller616). These communications can be made via signal paths625aor625bthat are internal to the source generator112and match network604respectively, or via signal path626, which is generally external to the source generator112and the match network204(although can comprise portions that are internal to the source generator112and the match network604).

In the illustrated embodiment, the signal path626is a bus (signals can travel in both directions and multiple signals can travel along the same path). However, in other embodiments, various components can have their own signal paths to the local controller612. In other embodiments, there can be more than one bus-type signal path, and in yet other embodiments there can be a combination of bus-like and non-bus signal paths.

In some embodiments, the signal path626can be replaced by communications via the transmission medium608. In other words, communications from the optional second sensor618to the local controller612can be modulated on the power signal transmitted between the source generator112and the match network604. Communications between the various components illustrated can be via a serial communication protocol such as RS-485. Alternatively, one or more of these communications can be made via a wireless connection or via a wired or wireless network. For instance, the signal path626can be implemented as a local area network (LAN).

Referring toFIG.6B, the local controller612bis arranged within the power delivery system600, but is not a part of or connected to the source generator112or the match network604. The local controller612bcan communicate with various components via a signal path626, which is configured as a bus. Again, a bus configuration is not required, and each component can have an isolated signal path to the local controller612b.

InFIG.6C, the local controller612cis coupled to or part of the match network604. Again any combination of bus-type signal paths or isolated signal paths can be used. As illustrated, the optional second sensor618in a first position618aand the impedance control system615communicate with the local controller612cvia signal paths625bthat are internal to the match network604. The source generator112(in particular, the RF engine613), the first sensor614, and the optional second sensor618in alternative position618b, communicate with the local controller612cvia the signal path626in a bus configuration.

The local controller612, the RF engine613, the first sensor614, the impedance control system615, and the optional second618and third611sensors can comprise any processor, such as, but not limited to, a central processing unit (CPU), a field programmable gate array (FPGA), a programmable logic device (PLD), a digital signal processor (DSP), or a combination of one or more CPU's, FPGA's, PLD's, and/or DSP's. Any of these components can comprise or be in communication with its own memory or a shared memory where the memory can be configured to store information such as configurations of the source generator112, bias supply408, and the match network604or trends in the power delivered to the plasma102. The memory can be part of the local controller612or can be part of either the source generator112or the match network604. In an embodiment, the memory can be a part of the RF engine613or the impedance control system615.

The local controller612can comprise hardware, software, firmware, or a combination of these. For instance, the local controller612can comprise a processor, memory, and software running on the processor that is configured to analyze data from the first, second, and or third sensors614,618,611and determine how and when to instruct the source generator112, match network604, and/or bias supply408to adjust internal parameters of those components.

The RF engine613, first sensor614, impedance control system615, and the optional second sensor618can each comprise logic such as a processor that receives instructions and transmits information to the local controller612. Alternatively, the local controller612can handle all logic and control functions for each of the RF engine613, first sensor614, impedance control system615, and the optional second sensor618.

The power delivery requirements can be programmed into the local controller612, can reside on a memory accessible by the local controller612, or provided by a user (user power delivery requirements). In an embodiment, the first, second, and third sensors614,618,611are either V-I sensors (capable of measuring voltage, current, and phase) or directional couplers able to measure phase. In some implementations only one of the two second sensor618positions (618aor618b) is implemented.

The transmission mediums608,610can be implemented as high power cables (e.g., coaxial cables) or transmission lines. They can also be electrical connections between an adjacent or connected source generator112and match network204. In an embodiment, the source generator112is connected to the match network604as part of a unified power delivery system600such that the transmission medium608is merely an internal electrical connection between two subcomponents of the power delivery system600. In another embodiment, the source generator112and the match network204are so interconnected that a transmission medium608does not exist. In other words, the source generator112and match network604can be part of a single box, container, package, or unit. Such an embodiment could entail greater integration of sub-components (e.g., power sources, memory, and processors, to name a few) and communications between the source generator112and the match network604. Some sub-components within the source generator112and match network604can be shared. For instance, the match network604can be made such an integral part of the source generator112that the source generator112and the match network604can both share a filter and/or final combiner of the source generator112.

In an embodiment, a power control system can comprise the local controller612, the first sensor614, and optionally the second sensor618. The power control system can be used to modify existing power delivery systems to enhance their power delivery capabilities as discussed above.

FIG.7illustrates an embodiment of a multi-generator power delivery system700. The power delivery system700comprises three generators702a,702b,702ceach with a match network704a,704b,704cused to minimize reflected power as the generators702a,702b,702cprovide power to a plasma102. A sensor714a,714b,714cis included for monitoring generator702a,702b,702cvoltage, current, phase, impedance, and power. The sensors714a,714b,714ccan be part of each generator702a,702b,702cor coupled to each generator702a,702b,702cor external to each generator702a,702b,702c. The sensors714a,714b,714crelay voltage, current, phase, power and impedance measurements to a local controller712.

The sensors714a,714b,714ccan also relay identifications of themselves including information such as configuration and operating parameters to the local controller712. The generators702a,702b,702cand the match networks704a,704b,704ccan also identify themselves to the local controller712, for instance via the RF engines713a,713b,713cand the impedance control systems715a,715b,715c, respectively.

The local controller712can manage communications between the generators702a,702b,702c, the match networks704a,704b,704c, and the sensors714a,714b,714c. The local controller712is also configured to pass instructions to the generators702a,702b,702cand the match networks704a,704b,704cregarding how and when to adjust internal parameters. In this way the local controller712enables the generators702a,702b,702cand the match networks704a,704b,704cto operate in unison and in a fashion that takes into account variations between components as well as operation of other components. In some instances, this unified operation of the power delivery system700can also consider non-electrical factors such as plasma chamber gas chemistry or processing end point. In an embodiment, a frequency of the generators702a,702b,702ccan be tuned while also tuning the match networks704a,704b,704c.

In this multi-generator embodiment, a particular challenge in the art is generating consistent power since each generator702a,702b,702csees the other generators702a,702b,702cthrough the transmission mediums710a,710b,710cor the plasma102(depending on the configuration). In other words, traditional multi-generator systems are plagued by cross talk interaction between the generators702a,702b,702c. By enabling the generators702a,702b,702cand match networks704a,704b,704cto communicate with each other via the local controller712and to be controlled with the local controller712taking into account the operation of all of these components simultaneously, consistent and accurate power can be provided to the plasma102.

In an embodiment, a user can interface with an external controller716, which is in communication with the local controller712. The external controller716can send and receive both instructions and data to and from the local controller712. User control of the generators702a,702b,702cand match networks704a,704b,704cis made via the local controller712by way of the external controller716.

While the local controller712is illustrated as being part of generator702a, it can also be a part of generator702bor generator702c. Alternatively, all other locations within the power delivery system700can also be used.

Furthermore, the local controller712can communicate with an RF engine713a,713b,713cof each generator702a,702b,702cand an impedance control system715a,715b,715cof each match network704a,704b,704c. In particular, the local controller712can communicate with and pass instructions to these subcomponents. In this way, the local controller712can instruct the generators702a,702b,702cand match networks704a,704b,704cto alter operating parameters such as pulse frequency and variable capacitor position, to name two non-limiting examples.

FIG.8illustrates another embodiment of a multi-generator power delivery system400.FIG.8differs fromFIG.7in that the sensors814a,814b,814care arranged at outputs of the match network804a,804b,804cinstead of at outputs of the generators802a,802b,802c. The sensors814a,814b,814care configured to characterize the power for each generator802a,802b,802cand match network804a,804b,804cby measuring voltage, current, phase, impedance, and/or power at the output of the match networks804a,804b,804cor en route to the plasma102.

The sensors814a,814b,814cand the generators802a,802b,802ccan identify themselves to the local controller812via the RF engines and the impedance control systems815a,815b,815c, respectively.

The power delivery system800can interface with users via an external controller816. The external controller816can be in communication with the local controller812and send and receive both instructions and data to and from the local controller812.

As in previous embodiments, the local controller812can be arranged as part of the generator802a, as illustrated, or as part of any of the other components within the power delivery system800or adjacent to any of these components, but still within the power delivery system800.

While impedance control systems815a,815b,815care illustrated for each match network804a,804b,804c, one of skill in the art will recognize that these can either represent separate hardware (or software or firmware) components, or a single hardware component comprising a separate logical block for each match network804a,804b,804c. In an alternative embodiment, a single impedance control system (not illustrated) may control operating parameters of all three match networks804a,804b,804c.

In another embodiment, the sensors814a,814b,814ccan be replaced by a single sensor located between the match networks804a,804b,804cand the plasma102. The single sensor can measure voltage, current, phase, impedance, and power just as the three sensors814a,814b,814cillustrated are configured to.

Although the generators802a,802b,802cand the match networks804a,804b,804care illustrated as communicating with the local controller812via the same signal paths (in a bus configuration), in other embodiments, each component may have a separate signal path to the local controller. Alternatively, the generators802a,802b,802cmay have one signal path to the local controller812while the match networks804a,804b,804chave another signal path to the local controller812. The sensors814a,814b,814ccan also have their own signal path to the local controller812.

FIG.9illustrates yet another embodiment of a multi-generator power delivery system500.FIG.9differs fromFIGS.7and8in that the sensors of those figures are replaced here by a single sensor914arranged at an input of the plasma102. The sensor914is configured to characterize the power for each generator902a,902b,902cand match network904a,904b,904c.

The power delivery system900can interface with users via an external controller916. The external controller916can be in communication with the local controller912and send and receive both instructions and data to and from the local controller912.

Although the generators902a,902b,902cand the match networks904a,904b,904care illustrated as communicating with the local controller912via the same signal paths (in a bus configuration), in other embodiments, each component may have a separate signal path to the local controller. Alternatively, the generators902a,902b,902cmay have one signal path to the local controller912while the match networks904a,904b,904chave another signal path to the local controller912.

While each external controller ofFIGS.7-9is illustrated as having its own signal path to the local controller, in alternative embodiments, each external controller can share the same signal path used by the sensor generators, and match networks use to communicate with the local controller.

Although the multi-generator embodiments illustrated inFIGS.7-9show three sets of generators, match networks, and sensors, in other embodiments, these configurations can be implemented with two or more sets of generators, match networks, and sensors. In one embodiment, there can be a single sensor rather than a sensor for each set of generators and match networks. The single sensor could measure power output locally for one generator and remotely for two generators. The single sensor could also remotely characterize impedance for all three match networks.

Referring next toFIG.10, shown is a general representation of an exemplary bias supply1008that may be used to realize the bias supplies408,508. As shown, the bias supply1008utilizes three voltages V1, V2, and V3. Because the output, Vout, is capacitively coupled through Cchuck, it is generally not necessary to control the DC level of Vout and the three voltages can be reduced to two by choosing one of V1, V2or V3to be ground (0V). A separate chucking supply107may be used so it is not necessary to control the DC level of Vout. If a separate chucking supply is not used, all three voltages can be controlled to control the DC level of Vout. Although not shown for clarity, the two switches S1, and S2may be controlled by a switch controller via electrical or optical connection to enable the switch controller to open and close the switches, S1, S2, as disclosed below. The depicted switches S1, S2may be realized by single pole, single throw switches, and as a non-limiting example, the switches S1, S2may be realized by silicon carbide metal-oxide semiconductor field-effect transistors (SiC MOSFETs).

In this implementation, the voltages V1, V2, and V3may be DC-sourced voltages. As shown, the first switch, S1, is disposed to switchably connect the first voltage, V1, to the output, Vout, through and inductive element and the second switch, S2, is disposed to switchably couple the second voltage, V2, to the output, Vout, through an inductive element. In this implementation the two switches connect to a common node,1070, and a common inductive element, L1, is disposed between the common node and an output node, Vout. Other arrangements of the inductive elements are possible. For example, there may be two separate inductive elements with one inductive element connecting S1to Vout and another connecting S2to Vout. In another example one inductive element may connect S1to S2and another inductive element may connect either S1or S2to Vout.

While referring toFIG.10, simultaneous reference is made toFIG.11, which depicts: 1) the voltage waveform of the bias supply1008that is output at Vout; 2) a corresponding sheath voltage; and 3) corresponding switch positions of switches S1and S2. In operation, the first switch, S1, is closed momentarily to increase, along a first portion1160of the voltage waveform (between voltage V0and Va) a level of the voltage at the output node, Vout, to a first voltage level, Va. The level Va is maintained along a second portion1162of the waveform. The second switch, S2, is then closed momentarily to decrease, along a third portion1164of the waveform, the level of the voltage waveform at the output node, Vout, to a second voltage level, Vb. Note that S1and S2are open except for short periods of time. As shown, the negative voltage swing along the third portion1164affects the sheath voltage (Vsheath); thus, a magnitude of Va-Vb may be controlled to affect the sheath voltage.

In this embodiment the third voltage, V3, is applied to the output node, Vout, through a second inductive element L2to further decrease a level of the voltage at the output node along a fourth portion1166of the voltage waveform. As shown inFIG.11, the negative voltage ramp along the fourth portion1166may be established to maintain the sheath voltage by compensating for ions that impact the substrate.

Thus, S1momentarily connects and then disconnects the first voltage, V1, to the output, Vout, through the first inductive element L1, and after a period of time, S2connects and then disconnects the second voltage (e.g., ground) to the output, Vout, through the first inductive element L1. The third voltage, V3, is coupled to the output, Vout, through a second inductive element L2. In this implementation, the first voltage, V1, may be higher than the third voltage V3, and the momentary connection and disconnection of the first voltage, V1, to the output Vout causes the voltage of the output, Vout, to increase along the first portion1160of the voltage waveform to a first voltage level, Va, and the first voltage level, Va, is sustained along the second portion of the waveform1162. The first voltage level Va may be above the first voltage, V1, and the second voltage, V2, (e.g., ground) may be less than the first voltage level, Va. The momentary connecting and then disconnecting of the second voltage, V2, causes the voltage of the output, Vout, to decrease at the third portion1164to the second voltage level Vb that is below the second voltage, V2(e.g., ground).

As an example, V1may be −2000 VDC; V2may be ground; V3may be −5000 VDC; V0may be −7000 VDC; Vb may be −3000 VDC; and Va may be 3000 VDC. But these voltages are merely exemplary to provide context to relative magnitude and polarities of the voltages described with reference toFIGS.10and11.

Referring next toFIGS.12A-12Cshown are possible arrangements of two DC voltage sources to provide the voltages V1, V2, and V3depicted inFIG.10. InFIG.12A, V2is grounded and forms a common node between the two DC voltage sources. InFIG.12B, V1is grounded and V2forms a common node between the DC voltage sources. And inFIG.12C, V1is grounded and forms a common node between each of the two DC voltage sources.

In some embodiments, as shown inFIGS.13A,13B, and13C, three DC voltage sources may be utilized to apply the three voltages V1, V2, and V3. As shown inFIG.13A, each of the three DC voltage sources may be coupled to ground, and each of the three DC voltage sources provides a corresponding one of V1, V2, V3. InFIG.13Bone of the DC voltages sources is grounded and the three DC voltage sources are arranged in series. InFIG.13C, one of DC voltages sources is disposed between ground and V2, and each of the DC voltage sources is coupled to V2.

The bias supply1008depicted inFIG.10is merely an example of a bias supply1008that may produce an output at Vout as shown inFIG.11. Other variations are shown and described the incorporated-by-reference patents referred to earlier herein. Also disclosed in the incorporated-by-reference patents are different modulation schemes that may be applied to the basic source waveform (at Vout) to achieve a desired distribution of ion energies and to control average power applied to the plasma chamber by the bias supply.

One modulation scheme comprises modulating the third portion1164of the voltage waveform to effectuate desired ion energies of ions impinging upon the workpiece103in the plasma chamber101. As an example, the bias supply408,508,1008may alternate a magnitude of the third portion1164of the voltage waveform between two or more levels to effectuate an alternating surface potential of the workpiece103in the plasma between two or more distinct levels. As another example, a slope of the fourth portion1166of the voltage waveform may be adjusted to change a level of current that is provided to an electrode104(to compensate for ion current that impinges upon the workpiece103) to achieve a desired spread of ion energies (e.g., around a center ion energy). Successful use of bias supplies408,508,1008as a bias generator in many plasma processing systems requires careful system design.

System Synchronization and Communication

Modulating supplies such as the source generators112, bias generators108, remote plasma sources205, and bias supplies408,508,1008can cause strong modulation of plasma properties. Examples of plasma properties, without limitation, comprise an impedance presented by the plasma, plasma density, sheath capacitance, and a surface potential of the workpiece103in the plasma102. As discussed above, the modulation of the voltage and/or current applied by the bias supplies408,508,1008is one potential cause of modulating plasma properties.

Source generators112may also modulate plasma properties by modulating electromagnetic fields impacting the plasma102. In particular, source generators112may pulse the power (e.g., RF power) that is applied by a source generator112. Moreover, a magnitude of voltage of the power applied by a source generator112may be changed. The addition of one or more additional source generators112adds additional complexity. And it is also contemplated that one or more bias supplies408,508,1008may modulate the voltage (Vout shown inFIG.10), and hence sheath voltage, while a source generator112is applying pulsed power. Thus, control over plasma properties (e.g., plasma density and ion energy) is challenging, and spatial control over the plasma properties is especially challenging.

As discussed above, a remote plasma source205may replace, or augment, a source generator112. But remote plasma sources205may also be modulating supplies that are configured to modulate plasma properties by modulating properties of gases in the plasma chamber101.

In addition to control challenges, one modulating supply may affect (e.g., in an adverse manner) operation of another modulating supply. As a specific, non-limiting, example, the bias supplies408,508,1008may impart power at a level that results in plasma modulation, which in turn, cause undesirable changes in the load impedance presented to a source generator112. In addition, strong plasma modulation can also cause aliasing of measurements of plasma properties. The aliasing may prevent accurate measurements of forward and reflected power; thus, preventing an operator from detecting damaging power levels and/or prevent proper control over at least one of the source matching network113or the bias matching network110.

Synchronization of equipment connected to the plasma system may mitigate the adverse effects of plasma modulation (e.g., damaging power and aliasing), and as a consequence, synchronization is highly desired. But the complex, time varying, aspects of plasma modulation (e.g., resulting from potentially many modulating supplies) can make synchronization difficult.

Referring toFIG.14, shown is a synchronization controller1416that is configured to synchronize constituent equipment of a plasma processing system that may comprise modulating supplies and other equipment that does not modulate the plasma102. As shown, the synchronization controller1416comprises a user interface1450, a waveform-characterization module1452, a waveform-repetition module1454, a waveform-communication module1456, and a synchronization module1458.

The depicted components of the synchronization controller1416may be realized by hardware, firmware, software and hardware or combinations thereof. The functional components of the synchronization controller1416may be distributed about the plasma processing system and duplicated in equipment that is connected to the plasma processing system. And as discussed further herein, the synchronization controller1416may be implemented as a master device or slave device.

The user interface1450enables an operator to interact with the plasma processing system so that the operator may control aspects of the synchronization and the operator may receive information about conditions of the equipment and the plasma chamber101. The user interface1450may be realized, for example, by one or more of a touch screen, pointing device (e.g., mouse), display, and keyboard.

The waveform-characterization module1452is generally configured to generate a waveform dataset that characterizes a waveform (e.g., a waveform of a modulation of the plasma or a waveform output (or desired to be output) by equipment) of the plasma processing system. The waveform-repetition module1454is configured to determine a repetition period, T, for a piece of equipment connected to the plasma system, and the waveform-communication module1456is configured to communicate the waveform dataset to at least one of the piece of equipment or another piece of equipment connected to the plasma processing system. The synchronization module1458is configured to send a synchronization pulse with a synchronization-pulse-repetition-period (which is an integer multiple of T) to one or more pieces of equipment connected to the plasma system.

While referring toFIG.14, simultaneous reference is made toFIG.15, which is a flowchart depicting a method that may be traversed in connection with a plasma processing system and the synchronization controller1416. As shown, plasma properties are modulated with a modulating supply where the modulation has a repetition period, T (Block1500). It should be recognized that in many embodiments T is the repetition period of the plasma modulation—not a cycle period of the modulating supply. As a consequence, the modulating supply may have an output with a repetition period that is different than the modulation of the plasma properties. For example, the modulating supply may have a repetition period of 200 microseconds and another modulating supply may have a repetition period of 500 microseconds resulting in the plasma102being modulated with a 1 millisecond repetition period, T. In some embodiments, T is a shortest length of time for which waveforms of all pieces of equipment that modulate the plasma properties of the plasma processing system is periodic with period, T.

As shown inFIG.15, the waveform characterization module1452may characterize a waveform with a repetition period, T, containing at least one of information about the modulation of the plasma or a desired waveform of a piece of equipment connected to the plasma processing system to produce a waveform dataset (Block1502).

Referring briefly toFIG.16, shown are: an exemplary output waveform1601of the bias supply408,508,1008; a waveform1603corresponding to is a calculated effective voltage at the surface of the workpiece103; a corresponding synchronization signal1604; and information about the waveform in the form of a waveform dataset1605. InFIG.16, an output waveform1601is the actual output of the bias supply bias supply408,508,1008(at Vout) with a fundamental period, T,1602. The waveform1603is a calculated effective voltage at the surface of the workpiece103(e.g., a sheath voltage that is the voltage of the workpiece103relative to the plasma102). Also shown is a synchronization pulse1604(also referred to as a synchronization signal1604) with a synchronization-signal-repetition-period that is an integer multiple of T. And the waveform dataset1605that comprises information about the waveform1603; thus, a characterized waveform (represented inFIG.16) is the waveform1603. It should be recognized that the waveform1603represents an alternating surface potential of the workpiece between two or more distinct levels (e.g., −500V and −1000V), but this is only an example and is not required. Alternatively, the characterized waveform may be an output waveform generated by a modulating supply, which inFIG.16is the output waveform1601of the bias supply408,508,1008. In yet another implementation, the characteristics of the waveform with a repetition period T comprise characteristics of the plasma properties such as plasma density, sheath capacitance, sheath potential, etc.

Referring again toFIG.15, the waveform dataset1605is sent by the waveform-communication module1456to the at least one piece of equipment connected to the plasma system (Block1504), and the synchronization module1458sends the synchronization signal1604with a synchronization-signal-repetition-period (which is an integer multiple of T) to at least one piece of equipment connected to the plasma system (Block1506). This method enables synchronization of pieces of equipment connected to the plasma processing system where the characterized waveform contains at least one of information about the modulation of the plasma or information about a desired waveform of a piece of equipment connected to the plasma processing system. It should be recognized that the waveform dataset may be communicated to a receiving-piece of equipment to control the receiving-piece of equipment (e.g., by directing the receiving-piece of equipment to provide a desired waveform). Or the waveform dataset may be informational (e.g., to provide information about the modulation of the plasma or to provide information about an output of a modulating supply).

AlthoughFIG.16depicts a specific example of a modulating supply that applies power with a waveform that enables control over ion energy in a region proximate to an electrode104, the waveform characterization (Block1506) is generally applicable to other waveforms that may represent aspects of plasma-related modulation (e.g., plasma density, plasma impedance, ion flux, etc.) or aspects of power applied by other equipment. For example, equipment coupled to the plasma processing system may comprise RF and DC generators, and in some implementations, the generator(s) are able to absorb power from the plasma processing system. It is also contemplated that in some embodiments one or more generators are a load that can only absorb power from the plasma processing system. Generators that are able to absorb power are useful for controlling spatial properties of an electromagnetic field in a plasma chamber by, e.g., avoiding standing waves in the chamber.

One or more of the source generators112may synchronize a property of the output of the source generator(s)112with the characterized waveform (that has the repetition period T). The property of the output of the source generator(s)112may be at least one of voltage, current, power, frequency, or generator source impedance. And the output of the source generator(s)112, for example, may comprise (within one repetition period) pulsed power followed by continuous wave power. And the waveform dataset may comprise a time series of values indicating one or more aspects of power (e.g., voltage, current, phase, etc.) for the repetition period. The source generator112may synchronize pulsing with a particular waveform applied by the bias supply408,508,1008that may, for example, modulate a magnitude of the negative voltage swing (the third portion1164) in a different manner while the source generator112is pulsing as compared to when the source generator112is operating in a continuous-wave mode of operation. This use case is only an example, and various other types of processing steps may prompt synchronization among pieces of plasma processing equipment.

In addition, the source generator112may advance or delay changes in a property of the output of the source generator112with respect to changes in the characterized waveform with a repetition period T. As discussed above, the characterized waveform in some implementations may characterize the modulation of the plasma properties. The characterized waveform may also characterize a waveform of the source generator112or another modulating supply (depending upon how the source generator112is configured to operate).

The equipment coupled to the plasma processing system (and synchronized as disclosed herein) is certainly not limited to modulating supplies. For example, the at least one piece of equipment that the dataset is sent to (Block1504) may comprise equipment that is configured to measure properties of the plasma processing system. For example, the measurements may comprise at least one of a measurement of plasma properties, properties of power delivered to the plasma system, or properties of gas delivered to the plasma system. By way of further example, the equipment that is configured to measure properties may comprise one or more of the source measurement and diagnostics system114and the bias measurement and diagnostics system111. Those of ordinary skill in the art recognize that the source measurement and diagnostics system114and the bias measurement and diagnostics system111may comprise one or more sensors (e.g., directional couplers and/or VI sensors) in connection with hardware to sample and analyze properties of power delivered to the plasma system (which may be used to measure plasma impedance as a plasma property). In the context of a plasma processing system utilizing the remote plasma source205, properties of the gas delivered to the plasma processing system may be measured (e.g., utilizing optical or other measurement techniques). As discussed herein, plasma modulation can cause aliasing of measurements of plasma properties, so synchronizing measurements to within time windows to avoid misleading transient values (or during time windows where modulation is at a local minima) is beneficial.

Other equipment that may be synchronized comprises matching networks. For example, the impedance matching network may synchronize measurements indicative of impedance with the characterized waveform. By synchronizing the measurements with time windows where measurements are not misleading (e.g., when there not large changes in power levels applied to the plasma), matching may be improved. Examples of impedance matching networks comprise the source matching network113and the bias matching network110.

The waveform dataset1605may be sent (Block1504) via digital communication link to one or more of the pieces of equipment coupled to the plasma processing system. The communication link may comprise the system control bus117, which may be realized by known digital links (for example, without limitation, ethernet). In many implementations, the waveform dataset1605may be communicated once, and then the synchronization pulse prompts each piece of equipment to operate in response to the waveform dataset in a repeating manner.

The synchronization signal may be sent (Block1506) via the near-real-time communication link119to equipment coupled to the plasma processing system. As an example, the near-real-time link may be an analog communication link to provide a single analog output with an identifiable fundamental pulse (also referred to as a “tick”)), and if required, update pulses (also referred to as “update-ticks”) are sent in between the fundamental pulses. In addition, the synchronization signal may comprise an indication of a start of the synchronization signal repetition period as well as at least one indication that a period of time since the start of the synchronization signal repetition period has elapsed.

The start of the synchronization signal repetition period may be indicated by a pulse of a first duration and the indication that a period of time since the start of the synchronization signal repetition period has elapsed may be indicated by a pulse of a second duration that is different from the first duration. For example, the first duration may be longer than the second duration or vice versa.

In some implementations, the synchronization signal comprises an indication of the start of the synchronization signal repetition period where the start of the synchronization signal repetition period is further modified at least once to indicate a time of day or to indicate that a new waveform is taking effect.

Referring toFIGS.17and18shown are flowcharts depicting activities carried out at a master piece of equipment and activities carried out at a slave piece of equipment, respectively. As shown inFIG.17, at a master piece of equipment, information on desired waveforms for equipment connected to the plasma processing equipment is obtained (Block1700), and a fundamental repetition period is determined (Block1702). A determination is also made to establish whether any intermediate synchronization pulses are necessary to maintain accuracy (Block1704). Waveform datasets are generated (Block1706) and then communicated to equipment connected to the plasma processing system (Block1708). In addition, synchronization pulses are provided to equipment connected to the plasma processing system (Block1710). As shown, intermediate synchronization pulses are provided to equipment if necessary (Block1712). And information about whether a sequence should change is also obtained (Block1714), and if the sequence should change (Block1716), then the activities described above with reference to Blocks1700to1714are performed again.

As shown inFIG.18, at a slave piece of equipment, a waveform dataset is received (Block1800), and the slave then waits for a start-of-sequence pulse to be received (Block1802) before setting a time to zero (Block1804). The slave equipment then waits for a pulse to be received (Block1806) and determines whether or not the pulse was a start-of-sequence pulse (Block1808), and if so, a time is set to zero (Block1810). If the received pulse is not a start-of-sequence pulse (Block1808), then the time is synchronized to a timing of the received pulse (Block1812). As shown, if a new waveform dataset is received (Block1814), then a new-waveform-dataset-received-flag is set (Block1816). If the new-waveform-dataset-received-flag is set (Block1818) and the received pulse is modified to indicate a change to a new dataset (Block1820), then the new-waveform-dataset-received-flag is cleared and the new waveform dataset is utilized (Block1822).

By utilizing precision oscillators, synchronization can be maintained with good precision. For example, using 50 ppm oscillators in all equipment, a change in a waveform can be predicted with better than 50 ns accuracy for a fundamental pulse repetition rate as low as 10 kHz. For longer pulse repetition periods one can add additional synchronization pulses every 100 μs to maintain synchronization within 50 ns accuracy.

Synchronization between a source generator112and bias supply408,508,1008may entail lowering voltage or cutting off voltage at the end of a given bias supply pulse. For example, it may be desirable to avoid ending an RF pulse in the midst of a bias supply pulse. Alternatively, pulsing or periodic reductions in voltage, may start and end at the same point/phase in the bias supply pulse, but for different pulses. In other words, it may be desirable to set the pulse on length equal to an integer number of bias supply pulses, whether or not the envelope pulse is in phase with a start or end to an individual bias supply pulse.

FIG.19illustrates a method1900of supplying power to a plasma load according to one embodiment of this disclosure. The method1900comprises a monitoring operation1902, an analyzing operation1904, and a relaying operation1906. The monitoring operation1902involves monitoring electrical characteristics of a power output of a generator (e.g.,202) and providing the electrical characteristics of the power output to a local controller (e.g.,612). The analyzing operation1904can comprise analyzing electrical characteristics of the power output (e.g., voltage, current, phase, impedance, power). The analyzing operation1904can also involve determining how the power delivery system (e.g.,200) can be operated in order to meet power delivery requirements in light of the monitored electrical characteristics. The relaying operation1906can involve relaying (passing or transmitting) instructions to the generator and the match network of the power delivery system, where the instructions can be based on the analyzing operation1904. The instructions can enable the simultaneous tuning of the generator and match network.

The previously described embodiments provide novel and nonobvious systems and methods to create laminate films, among other use cases. Examples such as diamond like carbon, which when deposited with plasma processing has very high stresses that can result in peeling of the film, can now be processed to incorporate low stress graphite or amorphous carbon layers so that the overall film still exhibits diamond like carbon properties but at lower stresses. In some films, it may be desirable to deposit the film in one period followed by a period where the plasma chemistry is modified by pulsing control and a high bias is applied to densify the film. Aspects described herein enable production of nano-level “Bragg” structures consisting of alternative layers with different optical properties produced by combining pulsing and bias voltage control in each respective period as illustrated earlier. Said another way, a first chemistry can be achieved for a first period of time to deposit a first layer, then a second chemistry can be achieved for a second period of time to deposit a second layer. This can be repeated numerous times to achieve a “Bragg” structure. The different chemistries can be achieved by variations in one or more of: bias voltage; duty cycle of two or more bias voltages; alterations in the timing of bias voltage, source pulsing; duty cycle of source pulsing; source voltage; and source voltage and pulsing in combination.

The methods described in connection with the embodiments disclosed herein may be embodied directly in hardware, in processor-executable code encoded in a non-transitory tangible processor readable storage medium, or in a combination of the two. Referring toFIG.20for example, shown is a block diagram depicting physical components that may be utilized to realize synchronization logic that may be implemented in equipment coupled to the plasma processing systems disclosed herein. As shown, in this embodiment a display portion2012and nonvolatile memory2020are coupled to a bus2022that is also coupled to random access memory (“RAM”)2024, a processing portion (which comprises N processing components)2026, an optional field programmable gate array (FPGA)2027, and a transceiver component2028that comprises N transceivers. Although the components depicted inFIG.20represent physical components,FIG.20is not intended to be a detailed hardware diagram; thus, many of the components depicted inFIG.20may be realized by common constructs or distributed among additional physical components. Moreover, it is contemplated that other existing and yet-to-be developed physical components and architectures may be utilized to implement the functional components described with reference toFIG.20.

This display portion2012generally operates to provide a user interface for a user, and in several implementations, the display is realized by a touchscreen display. In general, the nonvolatile memory2020is non-transitory memory that functions to store (e.g., persistently store) data and processor-executable code (including executable code that is associated with effectuating the methods described herein). In some embodiments for example, the nonvolatile memory2020comprises bootloader code, operating system code, file system code, and non-transitory processor-executable code to facilitate the execution of the methods described herein (e.g., the methods described with reference to ofFIGS.15and17-19).

In many implementations, the nonvolatile memory2020is realized by flash memory (e.g., NAND or ONENAND memory), but it is contemplated that other memory types may also be utilized. Although it may be possible to execute the code from the nonvolatile memory2020, the executable code in the nonvolatile memory is typically loaded into RAM2024and executed by one or more of the N processing components in the processing portion2026.

The N processing components in connection with RAM2024generally operate to execute the instructions stored in nonvolatile memory2020to enable control and synchronization among equipment coupled to a plasma processing system. For example, non-transitory, processor-executable code to effectuate methods of synchronously pulsing and changing voltages of the source generators and bias supplies may be persistently stored in nonvolatile memory2020and executed by the N processing components in connection with RAM2024. As one of ordinarily skill in the art will appreciate, the processing portion2026may comprise a video processor, digital signal processor (DSP), micro-controller, graphics processing unit (GPU), or other hardware processing components or combinations of hardware and software processing components (e.g., an FPGA or an FPGA including digital logic processing portions).

In addition, or in the alternative, the processing portion2026may be configured to effectuate one or more aspects of the methodologies described herein (e.g., methods of synchronously operating equipment of a plasma processing equipment). For example, non-transitory processor-readable instructions may be stored in the nonvolatile memory2020or in RAM2024and when executed on the processing portion2026, cause the processing portion2026to perform methods of controlling modulating supplies and other equipment. Alternatively, non-transitory FPGA-configuration-instructions may be persistently stored in nonvolatile memory2020and accessed by the processing portion2026(e.g., during boot up) to configure the hardware-configurable portions of the processing portion2026to effectuate the functions disclosed herein (including the functions of the synchronization controller1416.

The input component2030operates to receive signals (e.g., the synchronization signals or datasets with waveform characterization data) that are indicative of one or more aspects of the synchronized control between equipment of a plasma processing system. The signals received at the input component may comprise, for example, the power control and data signals, or control signals from a user interface. Signals received at the input2030may also comprise signals indicative of current, voltage and/or phase received from a V-I sensor or direction coupler, for example. The output component generally operates to provide one or more analog or digital signals to effectuate an operational aspect of control and synchronization between the equipment. For example, the output portion2032may out the synchronization signal and/or waveform datasets.

The depicted transceiver component2028comprises N transceiver chains, which may be used for communicating with external devices via wireless or wireline networks. Each of the N transceiver chains may represent a transceiver associated with a particular communication scheme (e.g., WiFi, Ethernet, Profibus, etc.). The transceiver component may enable connections with the control bus117, communication link119, and/or signal paths625,626.

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

As used herein, the recitation of “at least one of A, B or C” is intended to mean “either A, B, C or any combination of A, B and C.” The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.