If you can use one for a standard frequency determining element of an oscillator and the test sample in a identical oscillator you can use a frequency counter to get the dielectric constant. Two identical circuits should cancel out any noise. I used something like this for a soil moisture probe that worked well. Gordon Gordon Couger gcouger@couger.com www.couger.com/gcouger Stillwater, OK 405 624-2855 GMT -6:00 -----Original Message----- From: askane@west.raytheon.comTo: MEMS@ISI.EDU Date: Monday, April 26, 1999 1:16 AM Subject: Dielectric Constant Measurement in Polyimide > 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 > >