The Research on Non-destructive Testing Method of Sheet Resistance in Micro Area of Silicon Wafer Based on EIT Technology

A new method is described for determining the distribution of resistivity of semiconductor wafer and thin conducting films without contacting the surface of inside part. It has been termed as applied current tomography (ACT) which uses direct current injected through electrodes equally spaced around the periphery of the wafer or region to be measured , and then the resultant potential differences will be measured, from which the distribution of resistivity is calculated. The technique offers resolution and accuracy comparable to four-point probe methods and the wafer is not contaminated.