Abstract: A method for reducing power reflected towards a high frequency (HF) radio frequency (RF) generator during a cycle of a square wave voltage signal is described. The method includes receiving the square wave voltage signal, and dividing the square wave voltage signal into a pre-determined number of bins including a first bin and a second bin. The first bin has a different time interval than the second bin. The method further includes controlling the HF RF generator to generate an HF RF signal having a first frequency value during the first bin and a second frequency value during the second bin. The first frequency value is different from the second frequency value. The HF RF generator is controlled to reduce the power reflected towards the HF RF generator.

Abstract: Systems and methods for increasing a rate of processing a substrate using a square wave signal are described. One of the methods includes generating, by a low frequency (LF) radio frequency (RF) pulse generator, the square wave signal. The method further includes generating, by a high frequency (HF) RF signal generator, a sinusoidal RF signal and supplying the square wave signal to a filter coupled to an electrode of a plasma chamber. The method includes supplying the sinusoidal RF signal to an impedance matching circuit that is coupled to the electrode. The operation of supplying the square wave signal reduces power reflected towards the HF RF signal generator from the plasma chamber. The reduction in the power reflected towards the HF RF signal generator increases the rate of processing the substrate.

Abstract: A method for reducing reflected radio frequency (RF) power is described. The method includes receiving a voltage signal from an output of a match. The method further includes dividing the voltage signal into a plurality of bins and identifying a bin from the plurality of bins that includes a zero crossing. The bin is associated with a frequency of a high frequency (HF) signal. The method also includes applying a fixed multiplier to the frequency of the HF signal to generate a plurality of offsets. The method includes operating an HF RF generator according to the plurality of offsets during a time period in which the voltage signal is positive or negative.

Abstract: A method for achieving a first uniformity level in a processing rate across a surface of a substrate is described. The method includes receiving the first uniformity level to be achieved across the surface of the substrate and identifying a first plurality of duty cycles associated with a first plurality of states based on the first uniformity level. The first plurality of states are of a variable of a first radio frequency (RF) signal. The method further includes controlling an RF generator to generate the first RF signal having the first plurality of duty cycles.

Abstract: A tunable edge sheath (TES) system includes a coupling ring configured to couple to a bottom surface of an edge ring that surrounds a wafer support area within a plasma processing chamber. The TES system includes an annular-shaped electrode embedded within the coupling ring. The TES system includes a plurality of radiofrequency signal supply pins coupled to the electrode within the coupling ring. Each of the plurality of radiofrequency signal supply pins extends through a corresponding hole formed through a bottom surface of the coupling ring. The TES system includes a plurality of radiofrequency signal filters respectively connected to the plurality of radiofrequency supply pins. Each of the plurality of radiofrequency signal filters is configured to provide a high impedance to radiofrequency signals used to generate a plasma within the plasma processing chamber.

Abstract: A tunable edge sheath (TES) system includes a coupling ring configured to couple to a bottom surface of an edge ring that surrounds a wafer support area within a plasma processing chamber. The TES system includes an annular-shaped electrode embedded within the coupling ring. The TES system includes a plurality of radiofrequency signal supply pins coupled to the electrode within the coupling ring. Each of the plurality of radiofrequency signal supply pins extends through a corresponding hole formed through a bottom surface of the coupling ring. The TES system includes a plurality of radiofrequency signal filters respectively connected to the plurality of radiofrequency supply pins. Each of the plurality of radiofrequency signal filters is configured to provide a high impedance to radiofrequency signals used to generate a plasma within the plasma processing chamber.

Abstract: A method for achieving uniformity in an etch rate is described. The method includes receiving a voltage signal from an output of a match, and determining a positive crossing and a negative crossing of the voltage signal for each cycle of the voltage signal. The negative crossing of each cycle is consecutive to the positive crossing of the cycle. The method further includes dividing a time interval of each cycle of the voltage signal into a plurality of bins. For one or more of the plurality of bins associated with the positive crossing and one or more of the plurality of bins associated with the negative crossing, the method includes adjusting a frequency of a radio frequency generator to achieve the uniformity in the etch rate.

Abstract: A system having the low frequency RF generator is described. The low frequency RF has an operating frequency range between 10 kilohertz (kHz) and 330 kHz. The low frequency RF generator generates an RF signal. The system further includes an impedance matching circuit coupled to the low frequency RF generator for receiving the RF signal. The impedance matching circuit modifies an impedance of the RF signal to output a modified RF signal. The system includes a plasma chamber coupled to the RF generator for receiving the modified RF signal. The plasma chamber includes a chuck having a dielectric layer and a base metal layer. The dielectric layer is located on top of the base metal layer. The dielectric layer has a bottom surface, and the base metal layer has a top surface. The base metal layer has a porous plug and the bottom surface of the dielectric layer has a portion that is in contact with the porous plug.

Abstract: First, second, third, and fourth radiofrequency (RF) signal generators generate first, second, third, and fourth RF signals, respectively, having first, second, third, and fourth frequencies, respectively. The second and third frequencies are different specified harmonics of the first frequency. The fourth frequency is at least two orders of magnitude larger than the first frequency. An impedance matching system controls impedances for the first, second, third, and fourth RF signal generators. A control module is programmed to control: A) a first phase difference between the first and second RF signals, B) a second phase difference between the first and third RF signals, C) a first voltage difference between the first and second RF signals, D) a second voltage difference between the first and third RF signals. The first and second phase differences and the first and second voltage differences collectively control a plasma sheath voltage as a function of time.

Abstract: Systems and methods for controlling a plasma sheath characteristic are described. One of the methods includes determining a first value of the plasma sheath characteristic of a plasma sheath formed within a plasma chamber. The method further includes determining whether the first value of the plasma sheath characteristic is within a predetermined range from a preset value of the plasma sheath characteristic. The method also includes modifying a variable of a radio frequency (RF) generator coupled to the plasma chamber via an impedance matching circuit upon determining that the first value is not within the predetermined range from the preset value. The operation of modifying the variable of the RF generator is performed until it is determined that the first value of the plasma sheath characteristic is within the predetermined range from the preset value.

Abstract: A method for optimizing delivery of power to a plasma chamber is described. The method includes dividing each cycle of a low frequency (LF) radio frequency generator (RFG) into multiple time intervals. During each of the time intervals, a frequency offset of a high frequency (HF) RFG is generated for which the delivery of power is maximized. The frequency offsets provide a substantially inverse relationship compared to a voltage signal of the LF RFG for each cycle of the voltage signal. The frequency offsets for the time intervals are multiples of the low frequency. The substantially inverse relationship facilitates an increase in the delivery of power to the electrode. A total range of the frequency offsets from a reference HF frequency over the LF RF cycle depends on a power ratio of power that is supplied by the LF RFG and power that is supplied by the HF RFG.

Abstract: A method for controlling a limit on power supplied by a high frequency (HF) radio frequency (RF) generator is described. The method includes determining whether average power reflected towards the HF RF generator is less than a maximum limit, and determining whether power reflected towards the HF RF generator for a number of bins during a cycle is less than a predetermined threshold upon determining that the average power is less than the maximum limit. The method further includes determining whether a number of mistuned bins is greater than a predetermined number in response to determining that the power reflected towards the HF RF generator for the number of bins during the cycle is not less than the predetermined threshold. The method includes engaging a power limiter filter upon determining that the number of mistuned bins is not greater than the predetermined number.

Abstract: 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.

Abstract: A method for reducing reflected power associated with a high frequency (HF) radio frequency (RF) generator after a transition state is described. The method includes controlling the HF RF generator to divide a state of an HF RF signal into a plurality of sub-states. The plurality of sub-states include a first sub-state and a second sub-state. The method further includes controlling the HF RF generator to apply a first reference high frequency value during the first sub-state and a second reference high frequency value during the second sub-state. The method includes applying a first set of HF offset values from the first reference high frequency value during the first sub-state and applying a second set of HF offset values from the second reference high frequency value during the second sub-state.

Abstract: A method for reducing reflected radio frequency (RF) power is described. The method includes receiving a voltage signal from an output of a match. The method further includes dividing the voltage signal into a plurality of bins and identifying a bin from the plurality of bins that includes a zero crossing. The bin is associated with a frequency of a high frequency (HF) signal. The method also includes applying a fixed multiplier to the frequency of the HF signal to generate a plurality of offsets. The method includes operating an HF RF generator according to the plurality of offsets during a time period in which the voltage signal is positive or negative.

Abstract: Systems and methods for central frequency tuning are described. One of the methods includes receiving a voltage signal from an output of a match coupled to a low frequency (LF) radio frequency (RF) generator and a high frequency (HF) RF generator. The method further includes dividing the voltage signal into a plurality of bins for each cycle of an LF RF signal generated by the LF RF generator. The method also includes identifying a first bin from the plurality of bins during which a zero crossing occurs, accessing measurements of a parameter for occurrences of a pre-determined number of the plurality of bins, and calculating a frequency of operation of the HF RF generator for the first bin based on the measurements of the parameter. The method includes controlling the HF RF generator to operate at the frequency of operation during an occurrence of the first bin.

Abstract: A method for achieving uniformity in an etch rate is described. The method includes receiving a voltage signal from an output of a match, and determining a positive crossing and a negative crossing of the voltage signal for each cycle of the voltage signal. The negative crossing of each cycle is consecutive to the positive crossing of the cycle. The method further includes dividing a time interval of each cycle of the voltage signal into a plurality of bins. For one or more of the plurality of bins associated with the positive crossing and one or more of the plurality of bins associated with the negative crossing, the method includes adjusting a frequency of a radio frequency generator to achieve the uniformity in the etch rate.

Abstract: 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.

Abstract: A first radiofrequency signal generator is set to generate a low frequency signal. A second radiofrequency signal generator is set to generate a high frequency signal. An impedance matching system has a first input connected to an output of the first radiofrequency signal generator and a second input connected to an output of the second radiofrequency signal generator. The impedance matching system controls impedances at the outputs of the first and second radiofrequency signal generators. An output of the impedance matching system is connected to a radiofrequency supply input of a plasma processing system. A control module monitors reflected voltage at the output of the second radiofrequency signal generator. The control module determines when the reflected voltage indicates a change in impedance along a transmission path of the high frequency signal that is indicative of a particular process condition and/or event within the plasma processing system.

Abstract: An impedance match is described. The impedance match includes a housing having a bottom portion and a top portion. The bottom portion has match components and the top portion has an elongated body. A low frequency input is connected through the bottom portion of the housing, and the low frequency input is interconnected to a first set of capacitors and inductors. A high frequency input is connected through the bottom portion of the housing, and the high frequency input is interconnected to a second set of capacitors and inductors. An elongated strap extends between the bottom portion and the top portion of the housing. A lower portion of the elongated strap is coupled to the second set of capacitors and inductors and an upper portion of the elongated strap is connected to an RF rod at an end of the elongated body.