Characterization of PTC resistor pastes applied in LTCC technology.

This study deals with analyses of PTC (positive temperature coefficient) thick film resistor elements applied in LTCC (low temperature co-fired ceramics) technology. This study concerns the characterization of the electrical performance of PTC-elements placed in a different arrangement on a LTCC-multilayer substrate. Resistors are built-up on LTCC ceramic substrates and sintered in different configurations - on the surface of LTCC tape, in structure with embedded air cavity and co-fired in between two tapes. Three different cermet (ceramic -metallic) based thermistor compositions are used for this study. Electrical measurements were carried out in order to determine the temperature profile of the electrical resistance. TCR (Temperature Coefficient of Electrical Resistance) and the length / width ratio dependence on sheet resistance are evaluated. The influence of sintered configuration on the sheet resistance and TCR is discussed.