Low firing functional materials for application in power electronics

Abstract

In the past significant effort has been obtained on the miniaturization of electronic devices, for example in the field of cellular phones or other portables devices. Mainspring of this process is the huge success that has been obtained with giant integration densities on chip level. In contrast passive components are actually the most important bottlenecks in the upcoming miniaturization process, first of all for applications in power electronics. Especially in the field of electric mobility and innovative lighting technologies an increasing demand arises for miniaturized transformers and converters. Miniaturization of power electronic devices concentrates however the dissipation heat in a smaller volume, leading in most cases to higher operation temperatures. LTCC (Low-Temperature-Cofiring-Ceramic) as a ceramic multilayer interconnection technology has been employed for the development of 3D-high integrated electronic modules, marked by an excellent thermal robustness. Actual integration of inductors or capacitors in LTCC-boards is restricted to SMD's, limiting further miniaturization in an important manner. Hence the monolithic integration of inductors and capacitors into ceramic multilayer circuit boards is a straightforward approach to gain higher integration levels in power electronics. We report on the preparation and processing of low sintering materials for the implementation of ferrite cores into LTCC multilayer boards. Different semi-finished products based on ferrite powders have been elaborated. Sintering behavior of these materials has been studied and material compatibility with different standard LTCC materials was tested.