US 2002/0119660 A1 · Film thickness control using spectral interferometry

Abstract

A process for controlling a substrate processing operation such as a plasma etch operation. One embodiment of the method of the present invention forms a plasma within a substrate processing chamber to etch a wafer disposed within the chamber. The plasma emission is used by the process as a broadband light source. During the plasma etch process, a plurality of wavelengths of radiation reflected from the surface of the wafer being etched are measured with a spectrometer. These measurements are then compared using pattern recognition techniques to previous measurements taken during a previous plasma etch operation. Certain embodiments of the invention use principal component analysis (PCA) techniques to perform pattern recognition while other embodiment use programmed neural net pattern recognition techniques.

Claims20

Dependent claims

A method for controlling operation of a substrate processing chamber, said method comprising:

transferring a substrate into said substrate processing chamber;
performing a first substrate operation on the substrate disposed within the substrate processing chamber;
measuring a plurality of wavelengths of radiation reflected from an upper surface of said substrate during the first substrate processing operation;
converting each of the plurality of measured wavelengths into digital data;
and
comparing the digital data in real time with the digital data collected from a previous substrate processing operation using a principal component analysis pattern recognition technique.

3 more elements

A method for operating a substrate processing chamber to etch a substrate, the method comprising:

performing a calibration process within the substrate processing chamber by (i) transferring a first substrate into the chamber, (ii) etching the first substrate according to a first predetermined etch recipe, (iii) measuring a first plurality of wavelengths of radiation reflected from an upper surface of the first substrate during the etching step, (iv) converting the first plurality of wavelengths into digital data that includes a first set of digital data having data points representing times before and after a desired endpoint of the etch process, and (v) generating a reference principal component indicative of the desired endpoint from the first set of digital data;
thereafter, performing a production process within the substrate processing chamber by (i) transferring a second substrate into the substrate processing chamber, (ii) etching the second substrate according to a predetermined etch recipe substantially similar to the first predetermined etch recipe, (iii) measuring a second plurality of wavelengths of radiation reflected from an upper surface of the second substrate during the etching step, (iv) converting the second plurality of wavelengths into a second set of digital data, (v) generating a non-reference principal component from the second set of digital data, and (vi) comparing the non-reference principal component to the reference principal component and endpointing the etch process if the non-reference principal component matches the reference principal component.

Dependencies are inferred from the claim text.

Film thickness control using spectral interferometry

Life of this patent

Film thickness control using spectral interferometry

Life of this patent

Abstract

Claims20