Abstract
The production of LTCC substrates for wireless applications involves the co-firing of complex, multi-material structures. The materials must be compatible during the sintering process in terms of shrinkage behavior and materials interactions. The results of measurements of the shrinkage behavior of various LTCC materials made using a non-contact optical system will be presented. The behavior of bi-layers of LTCC materials during co-firing will be discussed in terms of both in-plane and thickness shrinkage as well as camber development. Methods of modeling the behavior during co-sintering of these and more complex structures will be discussed as well as techniques for measuring other materials properties necessary as input for the models. Constrained sintering will be discussed including an historical perspective as well as recent developments. Finally, an example of a deleterious materials interaction that occurs during post-firing of metallization onto vias will be presented.
