Materials and manufacturing technology for high reliability rigid-flex multilayer PCB for space 3D-electronics packaging

Abstract

Abstract Rigid-flex Multilayer PCB Technology enables the elimination of several connectors and bulky harness for interconnecting functional electronic systems. This minimizes packaging complexity and reduces performance degradation at high frequencies with an added advantage of reduced weight and volume in high-reliability space electronic packages. Here, only thermo-mechanically stable adhesiveless all polyimide flexible laminate cores and no-flow glass-polyimide prepregs are employed. To overcome the manufacturing issues like registration, coverlay protrusion into the rigid portions, and residual copper deposition at the intersections of flexible and rigid portions; a novel manufacturing process technology is proposed here. The technology has been successfully devised after choosing the most appropriate flexible, rigid, and low-flow prepreg materials. Herein, for the realization of rigid-flex multilayer PCB technology with 2-layers of flex and 8-layers of rigid to meet the functional requirements of the board is presented. The critical registration issues associated with the dissimilar rigid and flexible substrates are successfully addressed to achieve best-fit registration and obtain minimum annular rings of 50 μm in all the inner layers for high reliability. Experimental results manifest that incorporating rigid-flex multilayer PCB technology dramatically reduces weight (>30%) and volume (∼40%) to high-reliability space electronics 3D packaging for static and dynamic applications.