Patent ID: 7659734

Claim:
A method of detecting non-uniformities of a semiconductor wafer, comprising the steps of: providing a semiconductor comprising a wafer having a wafer surface; providing a contact potential difference sensor having a probe tip; providing a source of illumination energy in communication with the wafer surface; providing a mechanism providing variable illumination; directing the illumination energy at an area of the wafer surface that includes a sampling area located in proximity with the contact potential difference sensor probe tip; scanning the wafer surface laterally relative to the contact potential difference sensor while the surface of the semiconductor is illuminated; generating sensor data representative of changes in the contact potential difference between the sensor probe tip and the wafer surface as the sensor probe tip scans laterally across the wafer surface; and processing the contact potential difference sensor data to detect a pattern that represents a non-uniformity, wherein the non-uniformity is selected from the group consisting of chemical non-uniformities, physical non-uniformities, electrical non-uniformities, and combinations thereof.