CHARACTERIZATION OF DIELECTRIC TAPES FOR LTCC TECHNOLOGY USING CAPACITIVE METHOD IN THE FREQUENCY RANGE BETWEEN 1 kHz AND 1 MHz

In this paper, a capacitive method for characterization of LTCC tapes in the frequency range between 1kHz and 1MHz using HP 4277A LCZ meter is presented. The principle of operation using a parallel plate capacitor and equivalent circuit as a parallel connection of capacitance and a resistor is explained and characterization of test samples is measured. The fabrication process in LTCC technology and the causes that can produce the changing of characteristic parameters of substrates in fabrication are explained in detail. We indicated the importance of knowing permittivity in the function of frequency during projecting and simulating electronic components and circuits in LTCC technology. Measurements of complex permittivity, loss tangent, Q-factor based on the proposed formulas are made for LTCC tapes samples. Small variation of measured capacitance and loss tangent is obtained, approximately about 2% in whole frequency range. The value of loss tangent is approximately the same as the value specified by manufacturers. The calculated parameters for complex permittivity have bigger values then those recommended by manufacturers before firing. In the process of sintering, sheet density and microstructure of commercial tapes are changed for all used materials, causing changes of electric characteristics, especially permittivity. In the low frequency range, below 50 kHz, there is a higher variation of characteristic parameters. In this range, the parallel resistance of the equivalent circuit is on the top level of the instruments limit and these results are not reliable. A specific user-friendly program is developed which enables automatic control of measurement, recalculation of important values and processing of results.