Process for producing flip chip circuit board assembly exhibiting enhanced reliability

摘要

A process and combination of materials for underfilling a surface-mount IC device (12), such as a flip chip, for the purpose of increasing the thermal cycle fatigue life of the terminals (14) that attach the device (12) to a thin-laminate organic circuit board (10), such as a printed wiring board (PWB) or printed circuit board (PCB). The process parameters and materials, including the underfill (20), masking (22) and cleaning materials used, exhibit a synergistic effect that increases thermal cycle fatigue resistance to a level at which a flip chip processed in accordance with this invention is capable of reliably withstanding at least 1000 one-hour cycles between -40 DEG C. and 150 DEG C. The materials and the manner in which the device (12) and circuit board (10) are prepared for application of the materials are critical to eliminating tendencies for inconsistent reliability in underfilled SM devices.