Patent ID: 6255827
Filing Date: 2001-07-03
Classification: G01R

Abstract:
A method for locating the position of separated contact points on a substrate and determining if line continuity exists between said contact points comprising:(a) providing a first probe adapted to make an electrical connection to at least a first contact point on said substrate to be tested;(b) providing a second probe adapted to make an electrical connection to at least a second contact point on said substrate to be tested;(c) positioning the first probe at an ideal location of said first contact point to contact said first contact point on said substrate;(d) measuring the capacitance at the ideal location of the first contact point with respect to a reference plane of the substrate;(e) comparing the measured value of step (d) with a predetermined threshold capacitance value in order to determine if said first probe is making electrical contact with said first contact point on the substrate; and repositioning said first probe with respect to said substrate if said comparison of said measured value of capacitance indicates that said first probe is not in contact with said first contact point on said substrate; and independently moving said first probe with respect to a search point of a search pattern located around the ideal location of said first contact point of said substrate if said comparison of said measured value of capacitance indicates that said first probe is not in contact with said first contact point on said substrate until it is determined said first probe is making electrical contact with said first contact point on the substrate or all points of said search pattern have been tested;(f) positioning the second probe at an ideal location of said second contact point to contact said second contact point on said substrate;(g) performing an electrical resistance measurement test between said first and second probes;(h) comparing the measured value of step (g) with a predetermined threshold resistance value in order to determine if electrical continuity exists between said first and second contact points on said substrate.