An Investigation of Thick Film Resistor Materials' Properties During the Firing Process

Thick film resistor materials' microstructure, sheet resistivity and temperature coefficient of resistivity during the firing process in the temperature range between 350°C and 950°C were investigated. During firing the sheet resistivities at first decrease because of evaporation and/or oxidation of the organic phase and later, at higher firing temperatures, increase due to sintering of the glass phase and the rearrangement of conductive particles. The TCR is negative for firing temperatures below 450°C, due to the presence of partly pyrolysed organic vehicle, and positive for higher firing temperatures.