A method for multi-state pulsing to achieve a balance between bow control and mask selectivity is described. The method includes generating a primary radio frequency (RF) signal. The primary RF signal pulses among three states including a first state, a second state, and a third state. The method further includes generating a secondary RF signal. The secondary RF signal pulses among the three states. During the first state, the primary RF signal has a power level that is greater than a power level of the secondary RF signal. Also, during the second state, the secondary RF signal has a power level that is greater than a power level of the primary RF signal. During the third state, power levels of the primary and secondary RF signals are approximately equal.

Bias supplies and plasma processing systems are disclosed. One bias supply comprises an output node, a return node, and a switch network and at least one power supply coupled to the output node and the return node. The switch network and the at least one power supply configured, in combination, to apply an asymmetric periodic voltage waveform and provide a corresponding current waveform at the output node relative to the return node. A timing parameter estimator receives a digital representation of a full cycle of the voltage and current waveforms, and generates a pulse width control signal based on a crossing time that the current waveform crosses a threshold current value after falling from a positive peak current value to control the switch network.

A matchless plasma source is described. The matchless plasma source includes a controller that is coupled to a direct current (DC) voltage source of an agile DC rail to control a shape of an amplified square waveform that is generated at an output of a half-bridge transistor circuit. The matchless plasma source further includes the half-bridge transistor circuit used to generate the amplified square waveform to power an electrode, such as an antenna, of a plasma chamber. The matchless plasma source also includes a reactive circuit between the half-bridge transistor circuit and the electrode. The reactive circuit has a high-quality factor to negate a reactance of the electrode. There is no radio frequency (RF) match and an RF cable that couples the matchless plasma source to the electrode.

An etching method and a plasma processing apparatus form a recess with an intended shape. The etching method includes (a) providing a substrate including a silicon-containing film and a mask on the silicon-containing film. The silicon-containing film including a first region and a second region having a boundary therebetween as viewed in cross section in a direction perpendicular to a plane direction of the substrate. The boundary includes a slope extending in a direction inclined with respect to the plane direction. The method further includes (b) etching, after (a), the first region with first plasma generated from a first process gas to form a recess, (c) supplying, after (b), second plasma generated from a second process gas containing tungsten to the substrate, and (d) etching, after (c), the recess with third plasma generated from a third process gas. The recess crosses the slope in the cross section after (d).

A method for applying RF power in a plasma process chamber is provided, including: generating a first RF signal; generating a second RF signal; generating a third RF signal; wherein the first, second, and third RF signals are generated at different frequencies; combining the first, second and third RF signals to generate a combined RF signal, wherein a wave shape of the combined RF signal is configured to approximate a sloped square wave shape; applying the combined RF signal to a chuck in the plasma process chamber.

Systems and methods for synchronization of radio frequency (RF) pulsing schemes and of sensor data collection are described. One of the methods includes receiving, by an RF generator, a first set of one or more variable levels and one or more duty cycles of an RF signal. The method further includes receiving, by the RF generator from a pulse controller, a synchronization signal having a plurality of pulses. The method also includes generating, during a clock cycle of a clock signal, multiple instances of a first plurality of states of the RF signal in synchronization with the plurality of pulses of the synchronization signal. Each of the first plurality of states of the RF signal has a corresponding one of the one or more variable levels of the first set and a corresponding one of the one or more duty cycles of the first set.

A method for controlling a critical dimension of a mask layer is described. The method includes receiving a first primary parameter level, a second primary parameter level, a first secondary parameter level, a second secondary parameter level, and a third secondary parameter level. The method also includes generating a primary signal having the first primary parameter level, and transitioning the primary signal from the first primary parameter level to the second primary parameter level. The method further includes generating a secondary radio frequency (RF) signal having the first secondary parameter level, and transitioning the secondary RF signal from the first secondary parameter level to the second secondary parameter level. The method includes transitioning the secondary RF signal from the second secondary parameter level to the third secondary parameter level.

A power supply system controls the source impedance of a generator utilizing two amplifiers having asymmetrical power profiles in reference to a nominal load impedance that are diametrically opposite in reference to the nominal load impedance. Variations in power profiles may be achieved by using different topologies for each of the amplifiers or implementing a phase delay network. The output power from the first and second amplifiers may be combined using a combiner circuit or device and the output power from the combiner is transmitted to a plasma load. The output power of each amplifier may be independently controlled to alter one or more characteristics of the output power signal provided by the individual amplifiers. By changing the ratio of the output power of the first amplifier to the output power of the second amplified, the source impedance of the generators may be varied.

Provided is a generator including a power amplifier, at least one sampler, an RF output, a signal generator, a controller including a digital control portion and an analogue control portion, an analogue feedback path between the at least one sampler and the controller enabling an analogue signal representation of a signal to be provided to the controller, and a digital feedback path between the at least one sampler and the controller enabling a digital signal representation of the signal to be provided to the controller. The controller is configured to adjust the RF signal at the RF output from a first state into a second state based on the analogue signal representation and/or the digital signal representation.

A variable frequency and non-sinusoidal power generator includes a pulse module circuit, a slope module circuit, and first and second cooling systems. The pulse module circuit and the slope module circuit includes control switches, and generates at least one of a output currents and a output voltages by selectively turning on/off the control switches based on control signals. The first and second cooling systems are disposed at first and second sides of the control switches. A bias power having a variable frequency and a non-sinusoidal waveform is generated based on the control signals, at least one of the output currents and the output voltages.