Thick-film strain and temperature sensors on LTCC substrates

Purpose - Aims to evaluate different thick-film materials for use in strain sensors and temperature sensors on low-temperature co-fired ceramic (LTCC) substrates. Design/methodology/approach - LTCC materials are sintered at the low temperatures typically used for thick-film processing, i.e. around 850 degrees C, The thick-film resistor materials for use as strain and temperature sensors on LTCC tapes are studied. Thick-film piezo-resistors in the form of strain-gauges are realised with 10 k Omega/sq. 2041 (Du Pont)and 3414-B (ESL), resistor materials; thick-film temperature-dependent resistors were made from PTC 5093 (Du Pont), and NTC-4993 (EMCA Remex) resistor materials. Findings - The X-ray spectra of the 2041 and 3414-Bb low TCR resistors after drying at 150 degrees C and after firing display more or less the same peaks. The electrical characteristics of 2041 resistors fired on alumina and LTCC substrates are similar indicating that the resistors are compatible with the LTCC material. After firing on LTCC substrates the sheet resistivities and TCRs of the 3414-B resistors increased. Also, there is a significant increase in the GFs from 13 to over 25. Originality/value - Investigates the compatibility of thick-film materials and the characteristics of the force and temperature sensors.