Low Temperature Sintering and Dielectric Properties of Alumina-Filled Glass Composites for LTCC Applications Surendran Rajesh* and Heli Jantunen Microelectronics and Materials Physics Laboratories, University of Oulu, PO Box 4500, FI-90014, Finland Martin Letz Schott AG, Research and Technology Development, Hattenbergstr. 10, 55122, Mainz, Germany Sabine Pichler-Willhelm Schott Electronic Packaging GmbH, R&D Product Division Glass, Professor-Schott Str. 1, 84032, Landshut, Germany Glass + ceramic composites using lead-free ultralow-softening point glass matrices (brand names G018-249 and G018-250) with alumina fillers are investigated. The composites show good densification with near zero shrinkage at very low sintering temperature and do not show either the formation of secondary crystalline phases or dissolution of alumina. They further show no reactivity with the silver electrodes at a sintering temperature of 650°C and have permittivities of 9.5 and 8.8, loss tangents of 0.0068 and 0.0087 at 1 MHz for the samples containing G018-249 glass and G018-250 glass, respectively. Introduction Low temperature co-fired ceramics (LTCC) tech- nology has been extensively studied for various elec- tronic modules and devices requiring highly integrated packaging. LTCC technology is becoming essential in the development of multilayered devices and substrates, especially in wireless and high frequency applications. 1,2 Integration of passive components into LTCC is partic- ularly important because it corresponds to the trend of mobilization and miniaturization with electrical perfor- *rajeshayr@yahoo.co.in © 2011 The American Ceramic Society and Wiley Periodicals, Inc. Int. J. Appl. Ceram. Technol., 1–8 (2011) DOI:10.1111/j.1744-7402.2011.00684.x