Design, assembly, and reliability evaluation of next generation packaging solution for a System-On-Film (SOF)

Rapidly developing field of flexible electronics is driven by increasing demands for higher levels of integration. Flexible circuit technology offers numerous advantages and most important of them are geometrical and mechanical flexibility. One approach, known as chip-on-flex, achieves higher performance and circuit density by mating flexible circuits with surface mount technology components. Industry-wide chip-on-flex packaging solutions that have been used in high volumes are Tape-Carrier-Package (TCP) and Chip-On-Film (COF). The next generation system-level packaging solution being addressed in this research is System-On-Film (SOF) technology. SOF involves the integration of a large die alongside with surface mount passive devices on a flexible substrate. SOFs can be assembled using assembly processes and materials presently used in COF packaging. SOFs offer increased functionality within a single module, which means increased test coverage, and reduced overall costs during integration at the system-level. Due to reduced total cost of ownership and other advantages, SOF technology is being considered as an evolution (advanced version) of COF.;The factors that affect the development of SOF modules are design, assembly processes, handling and operating environment. The primary objective of this research is to investigate the effect of these factors on the mechanical integrity and reliability of the module. The secondary objective is to derive the design guidelines for both manufacturability and usage limitations. The fundamental understanding of the effects of design-process interaction will help in engineering an assembly process for improved module robustness. The effect of handling and operating environment factors on the module reliability are investigated using accelerated stress testing. During this research, it is found that an alternative approach is required for assessing the quality of the bonds formed during the die bonding process. Hence, this research also outlines a methodology to assess the quality of the die bonds.;The complicated task of selecting the appropriate design, process, handling and operating environment can be simplified by developing a system-level investigative approach. The overall solution to the problem is developed considering realistic constraints. Also, this research is able to highlight the complex interactions between different factors affecting the mechanical integrity and reliability of the SOF module.