LTCC SUBSTRATES CHARACTERIZED AT HIGH FREQUENCIES.

NIST staff recently completed measurements that resulted in a broadband characterization of the permittivity, loss tangent, and metal-loss of several classes of Low Temperature Co-Fired Ceramics (LTCC) substrates. The manufacturers of LTCC substrates expressed a need for improved measurement methods for characterizing the electromagnetic properties of LTCCs at a NIST-industry LTCC workshop held in Gaithersburg, MD, in October 1999. LTCC materials are increasingly being used in wireless and interconnect applications because of their ruggedness, high thermal conductivity, and low expansion coefficient. LTCC manufacturers need accurate permittivity and loss tangent measurements at microwave frequencies for use in CAD circuit design.

In response to this expressed need, NIST is working together to support the materials design and measurement needs of the emerging LTCC industry. Using the split-cylinder, split-post, and Fabry-Perot resonator methods, NIST scientists characterized substrates over a frequency range of 1 GHz to 60 GHz. The LTCC manufacturers are using the results of these measurements to verify their own permittivity and loss tangent measurement capabilities.