Patent ID: 6476604
Filing Date: 2002-11-05
Classification: G01N,H01L

Abstract:
A method for identifying high metal surface content substrate, comprising the steps of:providing a semiconductor substrate, said substrate having a surface; providing a source of rf energy, said source of rf energy providing rf waves having a frequency and an amplitude, said source of rf energy having a rf tuning circuit; providing a rf energy measurement apparatus, said rf energy measurement apparatus being able to generate a dc voltage that is indicative of the frequency and the amplitude of said rf energy provided by said source of rf energy; exposing the surface of said semiconductor substrate to said source of rf energy thereby including the surface of said substrate into the tuning circuit of the source of rf energy, changing the a first rf energy having a first frequency and a first amplitude of the rf energy created by said source of rf energy to a second rf energy having a second frequency and a second amplitude of the rf waves created by said source of rf energy due to metal being present in the surface of said substrate; entering said second rf energy into said rf energy measurement apparatus, said rf energy measurement apparatus creating a dc voltage level indicative of said second rf energy; providing a dc reference voltage level; comparing said dc voltage level created by said energy measurement apparatus which is indicative of said second rf energy with said dc reference voltage level; and determining if said dc voltage level created by said energy measurement apparatus is below or equal to said dc reference voltage level.