Abstract: Embodiments of a method of calculating the equivalent series resistance of a matching network using variable impedance analysis and matching networks analyzed using the same are provided herein. In one embodiment, a method of calculating the equivalent series resistance of a matching network includes the steps of connecting the matching network to a load; measuring an output of the matching network over a range of load impedances; and calculating the equivalent series resistance of the matching network based upon a relationship between the measured output and the load resistance. The load may be a surrogate load or may be a plasma formed in a process chamber.

Abstract: Methods and apparatus for controlling characteristics of a plasma, such as the spatial distribution of RF power and plasma uniformity, are provided herein. In some embodiments, an apparatus for controlling characteristics of a plasma includes a resonator for use in conjunction with a plasma reactor, the resonator including a source resonator for receiving an RF signal having a first frequency; a return path resonator disposed substantially coaxially with, and at least partially within, the source resonator; and an outer conductor having the source resonator and the return path resonator disposed substantially coaxially with, and at least partially within, the outer conductor, the outer conductor for providing an RF ground connection.

Abstract: Methods for determining characteristics of a plasma are provided. In one embodiment, a method for determining characteristics of a plasma includes obtaining metrics of current and voltage information for first and second waveforms coupled to a plasma at different frequencies, determining at least one characteristic of the plasma using the metrics obtained from each different frequency waveform. In another embodiment, the method includes providing a plasma impedance model of a plasma as a function of frequency, and determining at least one characteristic of a plasma using model. In yet another embodiment, the method includes providing a plasma impedance model of a plasma as a function of frequency, measuring current and voltage for waveforms coupled to the plasma and having at least two different frequencies, and determining ion mass of a plasma from model and the measured current and voltage of the waveforms.

Abstract: Methods for monitoring process drift using plasma characteristics are provided. In one embodiment, a method for monitoring process drift using plasma characteristics includes obtaining metrics of current and voltage information of a first waveform coupled to a plasma during a plasma process formed on a substrate, obtaining metrics of current and voltage information of a second waveform coupled to the plasma during the plasma process formed on the substrate, the first and second waveforms having different frequencies, determining at least one characteristic of the plasma using the metrics obtained from each different frequency waveform, and adjusting the plasma process in response to the determined at least one characteristic of the plasma.

Abstract: An electrostatic chuck in a reactor chamber has a cathode electrode insulated from ground, a chucking electrode insulated from the cathode electrode and a dielectric layer overlying the chucking electrode that provides a workpiece support surface. A D.C. chucking voltage supply is coupled to the chucking electrode. An RF power generator is coupled to the cathode electrode. A voltage sensing apparatus is coupled to the chucking electrode and to the cathode electrode to monitor the voltage difference between them during discharge after removal of RF and DC power at the conclusion of processing. The reactor includes a controller programmed to raise the lift pins during electrode discharge as soon as the voltage sensing apparatus detects equal voltages simultaneously on the chucking and cathode electrodes.

Abstract: A method for controlling a plasma in a semiconductor substrate processing chamber is provided. The method includes the steps of supplying a first RF signal to a first electrode within the processing chamber at a first frequency selected to cause plasma sheath oscillation at the first frequency; and supplying a second RF signal from the source to the first electrode at a second frequency selected to cause plasma sheath oscillation at the second frequency, wherein the second frequency is different from the first frequency by a differential equal to a desired frequency selected to cause plasma sheath oscillation at the desired frequency.

Abstract: RF ground return current flow is diverted away from asymmetrical features of the reactor chamber by providing bypass current flow paths. One bypass current flow path avoids the pumping port in the chamber floor, and comprises a conductive symmetrical grill extending from the side wall to the grounded pedestal base. Another bypass current flow path avoids the wafer slit valve, and comprises an array of conductive straps bridging the section of the sidewall occupied by the slit valve.

Abstract: RF ground return current flow is diverted away from asymmetrical features of the reactor chamber by providing a bypass current flow path. The bypass current flow path avoids the pumping port in the chamber floor and avoids the wafer slit valve, and is provided by a conductive annular baffle grounded to and extending from the wafer pedestal. Current flow below the level of the annular baffle can be blocked by providing one or more insulating rings in the sidewall or by providing a dielectric sidewall.

Abstract: An apparatus configured to confine a plasma within a processing region in a plasma processing chamber. In one embodiment, the apparatus includes a ring that has a baffle having a plurality of slots and a plurality of fingers. Each slot is configured to have a width less than the thickness of a plasma sheath contained in the processing region.

Abstract: A substrate cleaning chamber includes a contoured ceiling electrode having an arcuate surface that faces a substrate support and has a variable cross-sectional thickness to vary the gap size between the arcuate surface and the substrate support to provide a varying plasma density across the substrate support. A dielectric ring for the cleaning chamber comprises a base, a ridge, and a radially inward ledge that covers the peripheral lip of the substrate support. A base shield comprises a circular disc having at least one perimeter wall. Cleaning and conditioning processes for the cleaning chamber are also described.

Abstract: Methods for determining characteristics of a plasma are provided. In one embodiment, a method for determining characteristics of a plasma includes obtaining metrics of a plasma at two different frequencies, and determining at least one characteristic of the plasma utilizing the metrics. In another embodiment, a method for determining characteristics of a plasma includes obtaining metrics of current and voltage information for first and second waveforms coupled to a plasma at different frequencies, determining at least one characteristic of the plasma using the metrics obtained from each different frequency waveform. In another embodiment, the method includes providing a plasma impedance model of a plasma as a function of frequency, and determining at least one characteristic of a plasma using model.

Abstract: A method and apparatus for generating and controlling a plasma in a semiconductor substrate processing chamber using a dual frequency RF source is provided. The method includes the steps of supplying a first RF signal from the source to an electrode within the processing chamber at a first frequency and supplying a second RF signal from the source to the electrode within the processing chamber at a second frequency. The second frequency is different from the first frequency by an amount equal to a desired frequency. Characteristics of a plasma formed in the chamber establish a sheath modulation at the desired frequency.

Abstract: A method is provided for processing a workpiece in a plasma reactor chamber having electrodes including at least a ceiling electrode and a workpiece support electrode. The method includes coupling respective RF power sources of respective VHF frequencies f1 and f2 to either (a) respective ones of the electrodes or (b) a common one of the electrodes, where f1 is sufficiently high to produce a center-high non-uniform plasma ion distribution and f2 is sufficiently low to produce a center-low non-uniform plasma ion distribution. The method further includes adjusting a ratio of an RF parameter at the f1 frequency to the RF parameter at the f2 frequency so as to control plasma ion density distribution, the RF parameter being any one of RF power, RF voltage or RF current.

Abstract: In a plasma reactor chamber a ceiling electrode and a workpiece support electrode, respective RF power sources of respective VHF frequencies f1 and f2 are coupled to either respective ones of the electrodes or to a common one of the electrodes, where f1 is sufficiently high to produce a center-high non-uniform plasma ion distribution and f2 is sufficiently low to produce a center-low non-uniform plasma ion distribution. Respective center ground return paths are provided for RF current passing directly between the ceiling electrode and the workpiece support electrode for the frequencies f1 and f2, and an edge ground return path is provided for each of the frequencies f1 and f2. The impedance of at least one of the ground return paths is adjusted so as to control the uniformity of the plasma ion density distribution.

Abstract: A plasma reactor includes a ceiling electrode facing a workpiece support pedestal and a pedestal electrode in the pedestal and first and second VHF power sources of different frequencies coupled to the same or to different ones of the ceiling electrode and the pedestal electrode. The first and second VHF power sources are of sufficiently high and sufficiently low frequencies, respectively, to produce center-high and center-low plasma distribution non-uniformities, respectively, in the chamber. The reactor further includes a controller programmed to change the relative output power levels of the first and second VHF power sources to: (a) increase the relative output power level of the first VHF power source whenever plasma ion distribution has a predominantly edge-high non-uniformity, and (b) increase the relative output power level of the second VHF power source whenever plasma ion distribution has a predominantly center-high non-uniformity.

Abstract: A method is provided for processing a workpiece in a plasma reactor chamber. The method includes coupling, to a plasma in the chamber, power of an RF frequency via a ceiling electrode and coupling, to the plasma, power of at least approximately the same RF frequency via a workpiece support electrode. The method also includes providing an edge ground return path. The method further includes adjusting the proportion between (a) current flow between said electrodes and (b) current flow to the edge ground return path from said electrodes, to control plasma ion density distribution uniformity over the workpiece.

Abstract: A method for processing a workpiece in a plasma reactor chamber includes coupling RF power at a first VHF frequency f1 to a plasma via one of the electrodes of the chamber, and providing a center ground return path for RF current passing directly between the ceiling electrode and the workpiece support electrode for the frequency f1. The method further includes providing a variable height edge ground annular element and providing a ground return path through the edge ground annular element for the frequency f1. The method controls the uniformity of plasma ion density distribution by controlling the distance between the variable height edge ground annular element and one of: (a) height of ceiling electrode or (b) height of workpiece support electrode.

Abstract: A plasma reactor includes an electrostatic chuck in the chamber for supporting the workpiece, a ceiling electrode facing the electrostatic chuck and an ESC electrode in the electrostatic chuck with an electrostatic clamping voltage supply coupled to the ESC electrode. The reactor further includes at least a first RF bias source of an LF or HF frequency coupled to the pedestal electrode, and first and second VHF power sources of different frequencies coupled to the same or to different ones of the electrodes. The first and second VHF power sources are of sufficiently high and sufficiently low frequencies, respectively, to produce center-high and center-low plasma distribution non-uniformities, respectively, in the chamber.

Abstract: A method of processing a workpiece in a plasma reactor chamber includes coupling RF power via an electrode to plasma in the chamber, the RF power being of a variable frequency in a frequency range that includes a fundamental frequency f. The method also includes coupling the electrode to a resonator having a resonant VHF frequency F which is a harmonic of the fundamental frequency f, so as to produce VHF power at the harmonic. The method controls the ratio of power near the fundamental f to power at harmonic F, by controlling the proportion of power from the generator that is up-converted from f to F, so as to control plasma ion density distribution.

Abstract: A method and apparatus for confining a plasma are provided herein. In one embodiment, an apparatus for confining a plasma includes a substrate support and a magnetic field forming device for forming a magnetic field proximate a boundary between a first region disposed at least above the substrate support, where a plasma is to be formed, and a second region, where the plasma is to be selectively restricted. The magnetic field has b-field components perpendicular to a direction of desired plasma confinement that selectively restrict movement of charged species of the plasma from the first region to the second region dependent upon the process conditions used to form the plasma.