M.S. Thesis Presentation by Jennifer L. Venton
Friday, November 17, 2000

(Dr. Daniel Baldwin, advisor)

"Flip Chip on Flex for Low Cost Electronic Packaging"

Abstract

Over the past several years, flip chip technology has been heavily focused on developing and refining the next generation flip chip processes on rigid substrates.  Flip chip on flexible substrates offers a light weight, cost effective, and potentially smaller alternative to the rigid substrates currently used.  This high I/O flip chip on flex packaging research focuses on comprehensive reliability and performance testing, flip chip process development on flexible substrates, and process documentation. The strategy for this project is to implement FCOF with commercially available fast flow snap cure underfills and leverage current SMT equipment infrastructure.
The goal of this research is to characterize and implement the assembly process for this high I/O flip chip package with a low cost material system and assembly process which utilizes high speed SMT platforms.  The experimentation tackles issues such as: new interactions between material sets, material set compatibility and the effects on long term reliability performance, fundamental processing issues such as substrate warpage, substrate pad height variation and its impact on flip chip yield, and how to fixture flexible packages for high volume surface mount assembly.   Design of experiments is utilized to determine acceptable assembly processing windows for IC placement, fluxing, and the reflow soldering process.  Long term reliability testing is preformed to access the effectiveness of this package and assembly process from a consumer standpoint.