Lifetime prediction for mechanically stressed low temperature co-fired ceramics

Multilayer ceramics based on LTCC (low temperature co-fired ceramics) are gaining increasing interest in the manufacturing of high-integrated devices for microelectronic applications. In many applications the parts are exposed to mechanical stresses, which is an important issue regarding the reliability of the device. To predict the life time of LTCC multilayer devices, and to extend the application range of LTCC, basic mechanical data of this material are needed. In this paper sintered LTCC laminates are investigated concerning their flexural strength, crack growth rate, and life time prediction. The flexural inert strength of the investigated LTCC material is about 450 MPa. In applications with a stress level of 100 MPa, like mass flow sensors for the measurement of injected fuel quantities, acceptable lifetimes are achieved. This means that LTCC is an interesting material to fabricate devices, in which LTCC fulfils the requirements of a functional and structural material.