Nonlinear optical system for sensing the presence of contamination on a semiconductor wafer

   
   

First and second laser inputs are directed to a location on a semiconductor wafer to be interrogated. A first signal analyzer receives a first light signal at a first second-harmonic wavelength generated by the first laser input and converts the signal to a first electronic signal, thus monitoring the intensity of the first second-harmonic wavelength as a function of contamination. A second surface optical signal analyzer provides a similar function at a second second-harmonic wavelength generated by the second laser input and provides a second electronic signal. A third surface optical signal analyzer receives a third light signal at a sum-frequency wavelength generated by the first laser input and the second laser input on the semiconductor wafer to be interrogated and converts the light signal to a third electronic signal. An electronic signal analyzer compares the first, second and third electronic signals for determining the level of semiconductor wafer contamination.

 
Web www.patentalert.com

< Heat development apparatus having a temperature adjusting device

< Real-time method for maintaining formation stability and monitoring fluid-formation interaction

> Method and apparatus for determining track density during a servo-track writing operation

> Switching power source device

~ 00131