Patent ID: 6419801
Filing Date: 2002-07-16
Classification: G01J

Abstract:
A method for selecting at least one endpoint indicator for a plasma process to be run in a processing chamber and which has at least a first endpoint, said method comprising the steps of:running a first plasma process in said processing chamber; obtaining optical emissions of plasma in said processing chamber throughout at least a substantial portion of said running step, wherein said obtaining step comprises obtaining optical emissions which includes at least wavelengths from about 250 nanometers to about 1,000 nanometers, inclusive, which defines a first wavelength range, and at a first wavelength resolution throughout an entirety of said first wavelength range, wherein said first wavelength resolution is defined as a wavelength spacing between each adjacent pair of wavelengths obtained throughout said first wavelength range by said obtaining step, wherein said first wavelength resolution is no more than about 1 nanometer such that said obtaining step obtains said optical emissions at least at 751 different wavelengths; analyzing said optical emissions from said obtaining step to identify at least one said wavelength as a possible endpoint indicator candidate for said first plasma process, wherein said analyzing step comprises the steps of: generating a plot of intensity versus time for each individual said wavelength of said optical emissions obtained by said obtaining step based upon said first wavelength range and said first wavelength resolution, said generating step illustrating a time-based effect of said running step on an intensity of each individual said wavelength of said optical emissions obtained by said obtaining step, based upon said first wavelength range and said first wavelength resolution, wherein said generating step thereby generates a plurality of said plots, with each said plot being specific to a particular said wavelength within said first wavelength range, and wherein said generating step further thereby produces at least 751 said plots of individual said wavelengths; receiving information on a first time estimate for said first plasma process to reach said first endpoint; eliminating any said wavelength provided by said obtaining step, based upon said first wavelength range and said first wavelength resolution, whose corresponding said plot fails to display a distinct change in intensity at a time at least generally corresponding with said first time estimate, wherein each said wavelength from said eliminating step is not a said possible endpoint indicator candidate; and identifying at least one said plot from said generating step which displays a distinct change in intensity at a time at least generally corresponding with said first time estimate, wherein said wavelength which corresponds with said at least one plot from said identifying step is a said possible endpoint indicator candidate; selecting said wavelength, associated with said at least one said plot from said identifying step of said analyzing step, as a first endpoint indicator of said first endpoint for said first plasma process; and using optical emissions of said wavelength from said selecting step to call said first endpoint for subsequent executions of the same said first plasma process in the same said processing chamber.