| Summary: | 碩士 === 國立聯合大學 === 材料科學工程學系碩士班 === 95 === In this study, lead-free thick film resistor pastes were prepared by mixing ruthenium oxide (RuO2) with different volume ratios of the CaO-B2O3-SiO2 based glass. The resistors were fired on alumina substrates using a post-fired process in our laboratory and a commercial chip resistor process with size of 0805 (0.08 in × 0.05 in). Influences of different process parameters on the electrical properties of the post fired thick film resistors were investigated. The resistors were also embedded in low temperature co-fired ceramic (LTCC) substrates, influences of the interactions between the resistors and substrates on the electric properties of the resistor films were investigated.
Six metal oxides were added to the glass using as temperature coefficient of resistor (TCR) modifiers of the resistors, they were Nb2O5, MnO2, MoO3, Fe2O3, TiO2, and CuO. The resistor glasses with different types and amounts of TCR modifiers resulted in different physical properties. Different phase separation behaviors were observed with different microstructures in the resistor layers. The ring structures formed by the conductive particles in the resistor layers were determined by types of the glasses using in the embedded resistors. Thus, the variations on resistivity of embedded resistors were larger than post-fired resistors.
All of the lead-free chip resistors passed the short time overload (STOL) test and more than 85% of samples passed the load life test in this study. Lead-free resistor pastes can make thick film resistors with sheet resistivities in the range of 45~10016 Ω/□ and TCR values closed to zero were obtained by adjusting the amounts of the TCR modifiers.
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