A low cost mounting process for flip chips on FR-4 substrates

摘要

A low cost mounting process for flip chips on FR-4 substrates was developed and is introduced in the paper. Structure and layout of the bumped test chips and the printed circuit boards are presented. The selection of appropriate flux, the placement and the soldering process are discussed with respect to compatibility to regular surface mount technology. Since complete underfilling is a necessity for high reliability an experimental methodology was developed to study the underfilling process. A test program including humidity tests and thermal cycling was performed to evaluate the reliability of the assembled modules.