The development of poled polyimide dielectric layers for simultaneous testing and light guiding applications in MCM-Ds

Noninvasive techniques for measuring electric field strengths in multichip module (MCM) substrates can be extremely important in determining ultimate module performance. Certain polymers such as polyimide exhibit an electroop tic response, after appropriate doping and poling, that permits direct meas urement of the internal fields with a laser probe. We have built MCM circui t structures using electro-optic polyimides for the dielectric laver. We re port thermal, electrical, optical, and electro-optic propel-ties for these dielectric layers. The optical properties of doped and poled polyimides mak e them attractive for building optical waveguides. We report results for po led polyimide use in both multiple layer structures and optical waveguide f ormation, and recommend processing guidelines. Further development of doped and poled polyimides may permit optical and electrical interlayers on the same thin-film MCM-D structure. (C) 2001 Elsevier Science Ltd. All rights r eserved.