DuPontTM Green TapeTM 9K7 Low Temperature Co-fired Ceramic (LTCC) Low Loss Dielectric System for High Frequency Applications

The DuPontTM Green TapeTM 9K7 Low Temperature Co-fired Ceramic (LTCC) system is a major technological advancement for use in high frequency applications in consumer, telecommunications, automotive and military electronic devices. The system provides low electrical resistance at high frequencies; compatibility with low-cost silver conductors; feasibility for miniaturization; the ease to incorporate buried resistors & capacitors; and long term reliability. In this work, the new low loss dielectric LTCC systems consisting of tapes, gold and silver conductors, resistors, and capacitors are examined to evaluate the effects of chemistry, processing conditions, processing latitude, microstructure and dielectric properties. The 9K7 tape chemistry is based on a proprietary, partially crystallizable high refractory glass and ceramic fillers which form a fired “glass ceramic-ceramic-glass” LTCC composite structure. The high frequency properties include a dielectric constant of ~ 7.1 and dielectric loss of 0.0010 at ~ 9.5 GHz with little or no variation as a function of refires. Also demonstrated is the stability of the system and its long term reliability in terms of the functional properties such as wire bonding, soldered adhesion, surface smoothness and bulk microstructures.