Traditionally in the semiconductor industry, thin film measurements are done by sampling a pre-determined number of points on the film. This is true whether the wafer is patterned or not. Point measurements do not provide correct information on trend in thickness variation across the wafer surface. Such information is quite effective while developing new coating, deposition, etching or polishing processes. Hence, a system that can map film thickness across the whole wafer or a large area of the wafer will be very useful to process developers. In this paper, we will discuss a technique that can map film thickness across a large area in a relatively short amount of time. The approach has been breadboarded and its applicability demonstrated. Using a single wavelength, this technique makes it possible to characterize film thickness without having to know optical constants of the substrate material.

Date Published: 4 December 1998
PDF: 6 pages
Proc. SPIE 3491, 1998 International Conference on Applications of Photonic Technology III: Closing the Gap between Theory, Development, and Applications, (4 December 1998); doi: 10.1117/12.328639

Published in SPIE Proceedings Vol. 3491:
1998 International Conference on Applications of Photonic Technology III: Closing the Gap between Theory, Development, and Applications
George A. Lampropoulos; Roger A. Lessard, Editor(s)