Characterisation of the electrical performance of buried capacitors and resistors in low temperature co-fired (LTCC) ceramic

This paper describes the electrical characterisation of a novel integrated passive component technology developed using low temperature co-fired ceramic (LTCC) techniques which provides high quality buried capacitors, up to 7.8 nF/cm², and buried resistor materials in the range 100 ω/sq. to 20 kω/sq. The characterisation was undertaken to analyse the components' performance under the individual and combined effects of applied frequency (100 Hz-13 MHz), temperature (-60C to +160C), and DC voltage (-35 volts to +35 volts). The results seen when these applied parameters were varied with regard to one another show complex interactive behaviour which was a function of the materials used. The scope of the work (∼6500 buried LTCC capacitors and resistors) facilitated analysis of such effects on a statistical level and over a number of material batches. A series of electrical models were completed and two sets of predictive functions were derived for the capacitors and the resistors. The models employed data taken from measurements of cross-sections of a number of different component geometries, and the accuracy of the final models facilitated prediction of process related defects present where manufacturing parameters are not optimised. The predictive functions allow designers to confidently anticipate the electrical performance of the components over the entire working temperature range of the target application.