Recent progress in flexible moulding and reliability investigation of CSP and BGA-packages using advanced interconnection technology

During semiconductor industry development, almost the whole packaging segment has shifted to the far east. Only a few packagers remained in Europe, focused on large scale production. At the Fraunhofer IZM, Berlin, Germany, a plastic packaging line was designed for fast, flexible and qualified service in low scale packaging and prototyping. The line consists of an epoxy multi-chip die bonder, wire bonder, flip chip placement system, multi-plunger moulding system, laser marking/trimming station, lead forming and lead soldering. For solder ball placement of both flip chips and ball grid array (BGA) packages, a laser solder ball placer is used. This machine can place and simultaneously reflow solder balls of various materials and diameters. The IZM mould and assembly line was installed to offer small/medium sized production to industry. This center can also be used for package development. In this paper, recent applications such as mechatronics and combination of multichip flip chip processes on different carriers including encapsulation by moulding are demonstrated. For production of CSPs and tape-BGA, the fiber-push connection method was used as a key technology. All packages are subject to detailed reliability investigations. The paper focuses on the moisture sensitivity of underfill and moulding compounds. Results of accelerated aging tests and the failure mechanisms for chip scale packages and few-chip micro-BGAs are demonstrated. Improvements for processing conditions and material selection and design are discussed, in order to achieve packages with high reliability for harsh environmental conditions in automotive use.