Abstract: The present hot switching method and impedance matching circuit extends the tuning range of matching circuits to include increased power levels. The hot switching method and circuit includes coupling a controlled impedance network between an RF generator output and a plasma chamber input for matching impedances. The controlled impedance network includes an RF switch for switching a predetermined impedance. A device performance characteristic of the RF switch is determined. RF power is applied from the RF generator through the controlled impedance network to the plasma chamber. A signal characteristic of the impedance match is measured. The RF switch is controlled based upon the measured signal characteristic such that the impedance match is driven towards a predetermined matching range. The RF switch is switched any speed based upon the device performance characteristic.

Abstract: A phase detector which determines the phase based upon the output signals from a power coupler. The power coupler outputs a first signal and a second signal. The first and second signals are input to a magnitude detector which determines the magnitude of the relative phase between the first and second signals. The first and second signals are also input to a sign discriminator which determines the sign of the phase between the first and second signals.

Abstract: An adaptive plasma characterization system and method characterize a semiconductor plasma process using fuzzy logic and neural networks. The method includes the step of collecting input and output training data, where the input training data is based on variables associated with electrical power used to control a plasma chamber and results from execution of the plasma process. The method further includes the step of generating fuzzy logic-based input and output membership functions based on the training data. The membership functions enable estimation of an output parameter value of the plasma process, such that the membership functions characterize the plasma process with regard to the output parameter. Modifying the membership functions based on a neural network learning algorithm and output data provides ability to learn. Thus, etching process parameters such as etch rate, end point detection, and chamber maintenance can all be characterized in a manner that allows the system to operate autonomously.

Abstract: A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is comprised of two half bridges (S1A, S2A and S1B, S2B). Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes first and second rectifiers (D1, D2) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined first and second voltage, the respective rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

Abstract: A radio frequency (RF) probe head apparatus is provided for measuring voltage and current of an RF signal in a sampled transmission line. The probe head apparatus includes a conductive housing, a bus inside the conductive housing, a pair of connectors mounted on the conductive housing and configured to pass an RF signal into and out of the housing via the bus, a voltage pick-up board within the housing, and a current pickup board within the housing. The voltage pickup board has an analog processor responsive to an electric field around the bus to produce a first DC output indicative of a root-mean-square (RMS) value of the electric field. The current pick-up board has a second analog processor responsive to a magnetic field around the bus to produce a second DC output indicative of an RMS value of the magnetic field.

Abstract: An apparatus is disclosed wherein a dual directional harmonics dissipation filter includes an input terminal coupled to a RF power amplifier providing a radio frequency signal in a predetermined frequency range, an output terminal for providing the radio frequency signal to a load at the predetermined frequency range, a low pass filter connected between the input terminal and the output terminal, and a plurality of high pass filters coupled to the low pass filter wherein the plurality of high pass filters receive and dissipate signals in excess of the predetermined frequency range and wherein the plurality of high pass filter's effect on the impedance is offset at the input and output of the low pass filter.

Abstract: A half sine wave resonant drive circuit provides a greater duty cycle range of operation without a loss in power, particularly at higher frequencies. A resonant circuit is capacitivly coupled to a single switching device to provide the greater duty cycle range by recycling the gate charge of the switching device through the resonant circuit. A half sine wave drive signal is thereby produced from an input square wave signal. The driving amplitude is constant for operation over the range of duty cycles.

Abstract: A probe interface for an RF probe head improves the dissipation of heat resulting from RF power. The interface includes a conductor for transmitting RF power to a plasma chamber, and a sensing board for generating an analog signal based on the RF power. An electrically insulative bushing is disposed between the conductor and the sensing board, where the bushing is thermally conductive such that the bushing dissipates heat resulting from the RF power. By enabling the bushing to be thermally conductive, thermal instability is reduced and the overall RF power handling capacity increases.

Abstract: The present control circuit and method extends the operating range of digitally sampled control loops. A programmable output of a generator is controlled. The programmable output includes a an output level having a corresponding set point. The generator has a drive input that is driven to an actual drive point for controlling the output level of the programmable output. A set point corresponding to a requested output level is determined. A predicted drive point is then determined. The actual drive point of the generator drive input is forced to the predicted drive point. The output level of the programmable output is sensed. A digital output signal that is representative of the sensed output level is generated. The actual drive point of the generator drive input is controlled based on the digital output signal, such that the output level of the programmable output is controlled. The actual drive point corresponding to the requested output level is then stored.

Abstract: An arc control system includes a sputtering chamber that houses an anode and a sputtering target formed from a target material and serving as a cathode. A DC power supply provides a DC voltage between the cathode and anode such that a cathode current flows from the anode to the cathode. A resonant network is coupled between the DC power supply and the chamber. The resonant network has sufficient Q so that in reaction to an arc, the cathode current resonates through zero, causing a positive voltage to be applied between the cathode and anode. A reverse voltage clamp is coupled across the resonant network to clamp the cathode voltage to a predetermined reverse voltage. The reverse cathode voltage inhibits subsequent arcing by positively charging insulated deposits on the sputtering target. The arc control system limits the quantity of energy that is dissipated by the arc.

Abstract: A radio frequency (RF) probe analysis system has a broadband design. The analysis system includes a sampling unit for generating digital power signals based on a plurality of analog signals. The analog signals characterize power delivered from an RF power delivery system to a plasma chamber. The analysis system further includes a digital processing unit for generating a digital spectrum signal based on the digital power signals. The sampling unit simultaneously samples a first plurality of frequencies from the analog signals such the that digital spectrum signal defines signal levels for the first plurality of frequencies. The sampling unit may also simultaneously sample a second plurality of frequencies from the analog signals such that the digital spectrum signal further defines signal levels for the second plurality of frequencies. The broadband architecture of the sampling unit enables closed loop control of power delivered to the chamber to tolerances unachievable through conventional approaches.

Abstract: A rectifier circuit powers three power conversion modules using a three phase AC input without a neutral connection. First, second and third bridge rectifiers are connected to first, second and third phases of the three phase AC input and produce first, second and third rectified waveforms, respectively. A connection between the first, second and third bridge rectifiers forms a virtual neutral. Capacitors are connected across the bridge rectifies to filter the rectified waveforms and to create a DC rail voltage. The DC rail voltages feed power conversion modules. Two of the three power conversion modules remain powered at a decreased voltage level when the remaining power conversion module fails. Inductors are connected between the bridge rectifiers and the capacitors to further smooth the DC rail voltages and increase the power factor. Alternately, inductors are connected between the phases of the three phase AC input and the bridge rectifiers.

Abstract: A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is comprised of two half bridges (S1A, S2A and S1B, S2B). Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes first and second rectifiers (D1, D2) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined first and second voltage, the respective rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

Abstract: A method of controlling an output of a generator is provided. The output provides an output signal having a settling time to a load having an impedance. The settling time of the output signal is determined. The output signal is amplitude modulated with a modulation waveform. A sense signal is generated that is representative of the modulated output signal. The sense signal is sampled at a sampling time based upon the settling time of the output signal. A digital representation of the sampled sense signal is generated. The amplitude modulation of the output is controlled based upon the digital representation of the sampled sense signal.

Abstract: A technique for measuring the current, voltage and phase of a Radio Frequency (RF) power wave to an RF load, accounts for the finite length of the voltage and current pickups, and corrects for effects of standing wave components of voltage and current. Voltage and current are computed as complex functions of the voltage pickup signal and the current pickup signal, based on coefficients precalibrated for the predetermined radio frequency. Alternatively, a corrected current value can based on the corrected voltage value and complex load impedance. The correction coefficients can be obtained, for each of a plurality of calibrating radio frequencies within an RF range, from voltage and current pickup signals under conditions of (a) open circuit load, (b) short circuit load, (c) fixed known impedance load; and (d) one of voltage and current being applied at a precise input level to a known load from an RF calibration source.

Abstract: A radio frequency (RF) power generator system includes a power generator that generates a RF power signal that is output to a load. The RF generator generates a forward power feedback signal and a reverse power feedback signal. A controller receives the forward power feedback signal and the reverse power feedback signal. The controller generates a setpoint signal that is output to the power generator. A setpoint modifier receives the forward feedback signal, the reverse feedback signal and an external setpoint signal. The setpoint modifier calculates a forward power limit based on the forward and reverse power feedback signals. The setpoint modifier and outputs a modified setpoint signal to the controller based on one of the forward power limit and the external setpoint signal. The setpoint modifier and the controller can be integrated.

Abstract: An optical position sensor for a vacuum tuning capacitor employs optic fibers that are positioned adjacent a nut associated with the guide shaft. A threaded lead screw is rotated to lift the nut and move the capacitor from a fully-withdrawn home position to a tuning position. A first fiber has its terminus aligned with the terminus of a second fiber to define a gap. A flag or shutter on the nut is positioned in the gap to block the light path between the fibers when the nut is in the home position, but is out of the gap to allow passage of light otherwise. This produces normally on signaling, giving the position sensor a fail-safe capability. The sensor can be incorporated into a cap or cover of the tuning capacitor.

Abstract: A high power grounded-drain source follower RF amplifier circuit employs a high voltage MOSFET. The RF signal at the input is applied with respect to ground via an isolation transformer whose secondary feeds the signal between gate and source. The output is taken from the source with respect to drain, which is grounded. A 13.56 MHz 3 KW power amplifier topology with isolated RF input drive for each MOSFET die uses a pair of kilowatt power transistors or KPTs, in which there are multiple large area MOSFET dies, with the drain regions of the dies being formed over a major portion of the die lower surface. The drain regions are in direct electrical and thermal contact with the conductive copper flange. The source and gate regions are formed on the dies away from the flat lower surface. One or more pairs of multi-chip KPTs can be configured to design stable 2.5 KW, 5 KW and 10 KW RF plasma generators at 13.56 MHz.

Abstract: An RF plasma system employs frequency tuning to change the frequency of an RF generator within a frequency range to match the impedance of a plasma chamber. Forward power and reflected power magnitudes are obtained from a bidirectional sensor. The ratio of reflected power to forward power is obtained for one frequency, and then the frequency is changed. The tuning algorithm compares the ratio of reflected to forward power at the new frequency with the ratio obtained earlier. If this ratio is smaller, the frequency is changed again in the same direction, but if larger, then the frequency is changed in the other direction. These steps are iterated until the ratio of reflected to forward power reaches a minimum. The tuning algorithm can be implemented in hardware or in software.

Abstract: An RF probe for a plasma chamber picks up current and voltage samples of the RF power applied to an RF plasma chamber, and the RF voltage and current waveforms are supplied to respective mixers. A local oscillator supplies both mixers with a local oscillator signal at the RF frequency plus or minus about 15 KHz, so that the mixers provide respective voltage and current baseband signals that are frequency shifted down to the audio range. The phase relation to the applied current and voltage is preserved in the baseband signals. These baseband signals are then applied to a stereo, two-channel A/D converter, which provides a serial digital signal to a digital signal processor or DSP. A local oscillator interface brings a feedback signal from the DSP to the local oscillator. The DSP can be suitably programmed to obtain complex Fast Fourier Transforms of the voltage and current baseband samples.