Electrical properties of eco-friendly RuO2-based thick-film resistors containing CaO-ZnO-B2O3-Al2O 3-SiO2 system glass for AlN substrate

Abstract

The objective of this study is to prepare lead-free thick film resistor (TFR) paste compatible with AlN substrate for hybrid microelectronics. For this purpose, CaO-ZnO-B2O3-Al2O3-SiO 2 glass system was chosen as a sintering aid of RuO2. The effects of the weight ratio of CaO to ZnO in glass composition, the glass content and the sintering temperature on the electrical properties of TFR were investigated. RuO2 as a conductive and glass powder were dispersed in an organic binder to obtain printable paste and then thick-film was formed by screen printing, followed by sintering at the range between 750°C and 900°C for 10 min with a heating rate of 50°C/min in an ambient atmosphere. The addition of ZnO to glass composition and sintering at higher temperature resulted in increasing sheet resistance and decreasing temperature coefficient of resistance. Using RuO2-based resistor paste containing 40wt%glass of CaO-20.5%ZnO-25%B2O3-7%Al2O 3-15%SiO2 composition, it is possible to produce thick film resistor on AlN substrate with sheet resistance of 10.6ω/ and the temperature coefficient of resistance of 702ppm/°C after sintering at 850°C.