We have built a customized vertical scanning white light interferometer (SWLI) for characterization of freely suspended (no substrate) transparent 5 µm thick monolayer polymer films. These films that are used by the electronics industry are found in e.g. film capacitors. Quality control (QC) of such films is important with regards to capacitance accuracy and process yield. Devices currently used to characterize polymer films scan the surface point by point whereas we measure, using wide-field SWLI, the total focal volume (0.9 mm by 0.7 mm by 0.01 mm, with 1.5 μm lateral resolution using 6x magnification.) in one rapid (1 s) scan. The thickness profile of the sample is obtained as the difference between the first and second surface profiles. Inclusions, e.g. defects or intentionally introduced entities also carry interest with regards to the QC of polymer (capacitor) films. We obtained the inclusion distribution within the film volume (with a depth resolution of 20 nm and a lateral resolution comparable to that on the surface) from the changes in the refractive index observed within the film. The measurement generates data presented in multiple formats: 3-D picture of the scanned volume (revealing inclusions), surface topographic plots, cross-section of the surface, and depth profiles.

Date Published: 9 December 2004
PDF: 10 pages
Proc. SPIE 5578, Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education, (9 December 2004); doi: 10.1117/12.567057

Published in SPIE Proceedings Vol. 5578:
Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education
Marc Nantel; Glen Herriot; Graham H. McKinnon; Leonard MacEachern; Robert A. Weersink; Rejean Munger; Andrew Ridsdale, Editor(s)