High temperature capacitors and transient liquid phase interconnects for Pb-solder replacement

Downhole oil and gas exploration, as well as military electronics have been the main markets for high temperature electronics above 150 A degrees C. However, the use of wide band gap semiconductors, SiC and GaN, in power supplies and automotive applications, in addition to LED lighting, is increasing. These changes are driving the demand for improved capacitors and interconnect materials for packaging these. The development of high temperature multilayer ceramic capacitors (MLCC) with nickel inner electrodes is reviewed and recent developments highlighted. The application and properties of transient liquid phase sintered TLPS metal interconnects to replace solders in leaded MLCC are described in detail. The maximum shear stress capability of TLPS Cu-Sn and In-Ag surpasses Pb-based solders at higher temperatures up to 300 A degrees C, so they are excellent candidates to replace Pb-based solders in future high temperature electronics.