Electrical Properties of Low Temperature Cofired Ceramics with Integrated Bulk Metals

Constrained sintering allows the cofired integration of bulk metals in LTCC (low temperature cofired ceramics) instead of paste prints. A difficulty of such an integration is the application of the metallic structures on the sensitive unfired ceramic foils. The paper shows different techniques for solving this problem. Higher possible resolution and more precise edges are the advantages of bulk metal structures. Other results are improved electrical properties. Different kinds of conductor designs were used to figure out the electrical features in the fields of radio frequencies and high power applications. The reduction of transmission losses in triplate lines up to frequencies of 45 GHz will be shown and discussed. Coils for powers supplies were investigated and measured at lower frequencies. Higher specific conductivity and thickness of bulk lines allow the realization of inductors with higher quality factor and lower resistance. The advantages of the new cofiring technology for LTCC and the potential for different applications will be discussed.