Development Of Thick Film Resistors Co-fireable With Ceramic Substrate

Abstract

s A Thicl\-Film-Resistor-sS.steni cofireable with ceramic substrate is developed Resistors , electrodes and ceramic substrate are sintered at 900T under air atmosphere The resistors are composite of Ru-based pyrochlore, glass and some additives The electrodes are composite of Ag and glass The substrate is composite of a-Alumina and glass Effects caused by cofiring such as reaction between resistor film and Ag-electrode were sufficiently reduced Electrical linearity of the resistor related to chemical properties of Ru-pyrochlores and glass are also discussed T a b l e 1. Character is t ics of Cofi reable Resistor *Normalized to size of lmm2 and lkRisq 1. I n t r o d u c t i o n Recently low-temperature-firing-ceramic (LTFC) substrates are rapidly spreading there applications TDK CO have already developed LTFC multi-layered-substrate for high density hybrid ICs This system is made of a substrate composed of a-Alumina and SrO-SiO,-B,O,-glass w t h high mechanical strength and low dielectric constant, and Agconductor of low electrical resistivity To improve abilities and density of these hybrid ICs, we newly developed cofireable resistor system that features # Embedding resistors in LTFC substrate reduces size of # One-time firing decreases production costs # Electrical characteristics such as TCR(Temperature Constant of Resistance), VCR(Vo1tage Constant of Resistance), Noise-Index are equivalent to usual resistor system fired on alumina substrates The resistor system consists of two kind of compositions CFR-I series supports resistance lower than 3kRisq and CFR-2 series supports resistance higher than IkRisq Main conductive phase is Bi,Ru,O, for CFR-I, and Pb,Ru,O,, for CFR-2 respectively VCR parameters are measured thiough two stages w t h a resistance bridge At first stage, a tenth of rated-vo1tag.e I S applied to the resistor At second stage, ratedvoltage is applied The VCR wll be calculated as follows hybrid ICs V, Rated Voltage (Volt) R, Resistance under applying rated-voltage R, Resistance under applying 0 Ixrated-voltage Noise-Index are measured by QuanTech 3 15B Noise meter. TCR are measured from -50OC to +125OC. Ru-Pyrochlore -Glass-frit ---Additives Ceramic Green Tap= Punching Through-holes