N K Technology Ltd

John C Lam

Abdul Rahim Forouhi

Dale A Harrison

Eric Maiken

Christopher Rush

Erik Maiken

A collimated laser beam is directed towards the wafer bottom such that the impinging light is partially forward deflected along the vias' bottom edges. Concentric laser interference fringes occur on the wafer top from constructive and destructive interference between the forward deflected and directly through propagating laser. A top down optical image from a number of vias' top openings and a top down fringe image from the same vias' concentric fringe sets are processed to three dimensionally characterize the vias.

Three dimensional characterization of silicon wafer Vias from combined on-top microscopic and bottom-through laser fringes measurement

The present invention provides a method for inferring optical parameters of a sample in a predictive spectral range by use of the known values of the optical parameters in a predetermined measurement spectral range. The method of the present invention capitalizes on the Forouhi-Bloomer dispersion equations for the optical constants n and k.

Method of inferring optical parameters outside of a measurement spectral range

The present invention provides a method for monitoring a modifying-process taking place in a thin-film sample and thereby characterizing the sample thus modified, wherein the modifying-process is performed for purpose of improving physical properties of the sample. The present invention further provides a monitoring tool for characterizing various thin-film processes. Advantages of the method of the present invention are manifest in its non-intrusive nature, fast (or real-time) response, robust sensitivity, and versatility in a variety of thin-film processes. Another inherent advantage of the present invention is that an assortment of the &ldquo;n&k&rdquo; parameters can be obtained by using only measurement tool, in contrast to two (or more) simultaneous measurement tools used in the prior art.

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San Jose, CA, United States of America

John C Lam