Flip Chip Reliability on Dynamically Loaded Multi-Functional Spacecraft Structures

Abstract

Electronic packages for space flight are becoming increasingly dense to allow for increased processing power and functionality. This has resulted in further hybridization of electronics where active devices are no longer surrounded by there own case or component package and are directly attached to the substrate. Chip-on-board approaches are being qualified for space flight use with flip chip approaches required to meet smaller volume requirements. These bare die attachment solutions are resulting in electronic sub-systems that have significantly lower weight and volume than state-of-the-art designs. Incorporating electronic traces or signal paths directly into the spacecraft or instrument structure can provide a significant savings in weight and volume. In addition, local computer processing power, increased operational speed and larger memory storage are achievable by using embedded or direct chip attach design methods. Recent developments in printed circuit board fabrication processes has given printed circuit boards increased strength and stiffness by incorporating single or multiple carbon graphite weave layers within the printed circuit board structure during the lamination fabrication process. Previous technology development work has demonstrated the significant mechanical yield strength and stiffness of multifunctional structures when printed circuit boards are laminated with graphite weave made from carbon fiber strands. Standard printed circuit board planar geometries with unique design features are used to construct three dimensional structural elements comprising a subsystem multi-functional structure.