Thermomechanical reliability of LTCC solder attachments

Low temperature Cofired Ceramic (LTCC)- based Multilayer Ceramic Integrated Circuits (MCIC) developed within the Microelectronics and Physical Sciences Lab (previously in the Solid State Research Center, SSRC) of Motorola are finding use in many wireless applications due to the advantages of RF function integration, and size reduction. To integrate MCIC applications on a PCB, a variety of solder attachment technologies have been developed over the years. These include ball grid array (BGA), and the MCIC side interconnects for lower profile cellular phone applications. These board-level solder attachments are comprised in dissimilar materials that expand or contract at different rates on various stages of thermal excursions: process cycle and operation cycle. In this paper, the thermomechanical reliability aspect of BGA and side interconnects were examined.