An apparatus for inspecting a sample for defects includes a signal generator for generating a signal and a device for splitting the signal into two separate signals which have substantially equal phase and magnitude. A sensor radiates the two signals on the sample and receives the two signals reflected from the sample. A device is provided for determining a difference between the two signals reflected from the sample without unwanted influence of variations of distance between the sensor and sample, and reflections from nearby sample edges and boundaries. A defect is determined to exist when a difference is found between the two reflected signals.
R. Zoughi et al., "Method and Apparatus for Nondestructive Sample Inspection," The Curators of the University of Missouri, Mar 2007.
Electrical and Computer Engineering
Patent Application Number
US 7,190,177 B2
© 2007 The Curators of the University of Missouri, All rights reserved.