Some remarks about relations between processing conditions and microstructural, electrical as well as stability properties of LTCC resistors (original) (raw)

This paper presents the correlation between processing conditions and microstructural, electrical and long-term stability properties of surface or buried LTCC resistors. The microstructure development (investigated by X-ray powder diffraction, scanning electron microscopy and energy dispersive X-ray analyses) is analysed for components made of three various resistive pastes with 10 kohm/sq. nominal sheet resistance (CF 041, DP 2041, ESL 3414B) prepared in/on DP 951 ceramic tape. The resistors were fired at standard (850 o C/15 min, 875 o C/15 min) or nonstandard (950 o C/15 min or 950 o C/180 min) temperature profile. Sheet resistance, hot and cold temperature coefficients of resistance, dependence of resistance in a wide temperature range, current noise index and their dependencies on resistor's aspect ratio and processing conditions have been measured as basic electrical properties. Moreover all processing variants of resistors were subjected to the step-increased long-term thermal aging at five different temperatures -162, 207, 253, 300 and 350 o C (the samples were kept at every temperature for 200 hours). Both the relative resistance changes and the changes of hot temperature coefficient of resistance versus the storage time and the temperature have been measured and analyzed.