Abstract: The present invention is directed to a gas line electron beam exciter, gas line electron beam excitation system and method for exciting a gas using an electron beam exciter. The electron beam exciter generally comprises a variable density electron source for generating a cloud of electrons in an electron chamber and a variable energy electron extractor for accelerating electrons from the electron chamber as an electron beam and into an effluent stream for fluorescing species in the effluent. The electron density of the electron beam is variably controlled by adjusting the excitation power applied to the variable density electron source. The electrons in the electron chamber reside at a reference electrical potential of the chamber, typically near ground electrical potential.

Abstract: The present invention is directed to a gas line electron beam exciter, gas line electron beam excitation system and method for exciting a gas using an electron beam exciter. The electron beam exciter generally comprises a variable density electron source for generating a cloud of electrons in an electron chamber and a variable energy electron extractor for accelerating electrons from the electron chamber as an electron beam and into an effluent stream for fluorescing species in the effluent. The electron density of the electron beam is variably controlled by adjusting the excitation power applied to the variable density electron source. The electrons in the electron chamber reside at a reference electrical potential of the chamber, typically near ground electrical potential.

Abstract: The present invention is directed to a system, method and software product for creating a predictive model of the endpoint of etch processes using Partial Least Squares Discriminant Analysis (PLS-DA). Calibration data is collected from a calibration wafer using optical emission spectroscopy (OES). The data may be non-periodic or periodic with time and periodic signals may be sampled synchronously or non-synchronously. The OES data is arranged in a spectra matrix X having one row for each data sample. The OES data is processed depending upon whether or not it is synchronous. Synchronous data is arranged in an unfolded spectra matrix X having one row for each period of data samples. A previewed endpoint signal is plotted using wavelengths known to exhibit good endpoint characteristics. Regions of stable intensity values in the endpoint plot that are associated with either the etch region or the post-etch region are identified by sample number.

Abstract: The present invention is directed to a system, method and software product for creating a predictive model of the endpoint of etch processes using Partial Least Squares Discriminant Analysis (PLS-DA). Calibration data is collected from a calibration wafer using optical emission spectroscopy (OES). The data may be non-periodic or periodic with time and periodic signals may be sampled synchronously or non-synchronously. The OES data is arranged in a spectra matrix X having one row for each data sample. The OES data is processed depending upon whether or not it is synchronous. Synchronous data is arranged in an unfolded spectra matrix X having one row for each period of data samples. A previewed endpoint signal is plotted using wavelengths known to exhibit good endpoint characteristics. Regions of stable intensity values in the endpoint plot that are associated with either the etch region or the post-etch region are identified by sample number.

Abstract: A test structure and a method of using it for measuring submicron linewidths. Diffraction gratings are made with lines having an unknown linewidth. The grating has a pitch comprises of multiple lines and multiple spaces. This permits a wider "effective pitch" resulting in an increased number of observable diffraction orders. Each order provides an intensity measurement, which can be substituted into a diffraction intensity equation in which intensity is a function of linewidth and other unknown variables. At least as many intensity measurements are obtained as are unknown variables so that a system of equations can be solved for the linewidth. In practice, if the grating lines are made in the same manner as other lines of a product, the width of the latter can be inferred.

Abstract: A method and apparatus for measuring submicron linewidths, using diffraction gratings. A set of "fixed-linewidth variable-pitchwidth" test gratings has a number of gratings, each grating having the same linewidth but having different pitchwidths. These gratings are illuminated to form diffraction patterns. A set of peak intensities of the first or second order diffraction image from each grating is recorded. Either of these intensity values forms a curve around an extrema, which represents the intensity from a grating whose pitchwidth is equal to one-half the linewidth.