DIELECTRIC CHARACTERIZATION OF EMBEDDED CAPACITANCE FILMS AT MICROWAVE FREQUENCIES
Authors: J. Obrzut and R. Nozaki Company: NIST, Polymers Division Date Published: 11/1/2000
Abstract: The dielectric permittivity and impedance characteristics were evaluated for high-dielectric constant polymer composite films that are being developed by the industry for Embedded Decoupling Capacitance applications. In order to extend the measurements to the microwave range, we developed a new testing methodology. The film specimen is treated as a distributed network consisting of a transmission line with the capacitance terminating a coaxial air-line. The theoretical model takes into consideration the wave propagation in the specimen section, thus eliminating limitations of the lumped element approximations. The implemented coaxial test fixture utilizes a simple 3 mm diameter disk test specimen. Using the new test technique, the dielectric permittivity of several EDC materials was evaluated at frequencies from 100 MHz to 10 GHz, and the impedance characteristics were determined directly in the time domain. The mechanism of dielectric relaxation in high dielectric constant films was studied using model polymer resins filled with ferroelectric ceramic powder. Based on these results, the desirable materials dielectric characteristics are discussed from the view point of designing efficient embedded decoupling capacitance for high-speed circuits.