Progress on LTCC Materials and Its Applications

    Multilayer microwave high-pass filter with a central frequency of 1.9 GHz has been successfully fabricated on the LTCC (Low Temperature Co-Fired Ceramic) product line with an advanced tape casting process in Zhejiang Zhengyuan Electric Co., Ltd, which owns the specifications of low insertion loss, high attenuation and small size (2.5×3.2×1.5 mm3). Designed as surface-mountable filters using the LTCC technology, they take much less time to calibrate, and effort to design the electric circuit, making it a good candidate in WLAN, DSTV and 3G mobile phone fields. 

   The LTCC fabrication is composed of two major aspects: the LTCC materials and processing technology, in which the materials play a fundamental and important role. There are only a few varieties of LTCC materials available, made by international enterprises, with a dielectric permittivity of 6-10.  Most of them are used in multilayer substrates, chip inductors, Bluetooth modules and IC packages, which cannot meet the multi-purpose demands. The LTCC materials, with a high permittivity larger than 60, are good candidates in making small-sized multilayer filters and antennas etc.

   The Research Center of Information Materials and Devices, SICCAS, has been dedicating on LTCC materials research for many years, having successfully developed series materials with the dielectric permittivity in the range of 7 - 200. The collaborations between SICCAS and Zhengyuan Electric Co., Ltd on the experimental research of LTCC technology started in 2007. The scientists have made efforts on adjustments of material compositions and fabrication technology to meet the requirement of stable mass production, especially solving the problems on the interface reaction between LTCC tapes and Ag electrodes during co-firing process. The breakdown electrical field of the dielectric was improved compared with the previously used materials imported from a foreign company. Right now the LTCC materials and the process show well technological stability and repeatability for batch production. The success in multilayer high-pass filters research indicates that the SICCAS has the knowledge and can offer a range of SMD filters for frequencies up to several GHz for low pass, band pass, high pass or band stop filter applications using our LTCC technology.

   Research Center of Information Functional Materials and Devices