Hello all, I am currently working with 15 micron thick, spin-on polyimide films. The films are hard-baked following patterning. Since these films are for a microwave/RF application (I'm fabricating tranmission lines on the polyimide, substrate is Si), I'm interested in measuring the dielectric constant and dielectric loss tangent for these films, following the curing step. I would like to know the variation in dielectric constant, loss tangent as a function of curing times, temperatures, etc... As far as I know the easiest way to do this is to fabricate a capacitor, with the polyimide as the dielectric and perform measurements usings the C-V meter. An alternative approach is to fabricate transmission lines, measure S-parameters, and extract the dielectric constant from the data... I'd be interested in performing an actual physical measurement, if possible, rather than rely on a functional device/component... Any suggestions would be appreciated... Thanks, Avi Kane Raytheon Systems Company askane@west.raytheon.com