Author: Michael Meilunas
Description: This document provides material requirements, inspection guidelines and process recommendations for Pb-free area array assembly based upon our consortium sponsored research which covered a range of laminate and flex based BGAs and CSPs with pitches down to 0.5mm including Wafer Level CSPs (WL-CSPs). Much of the following is also relevant to other components such as ceramic BGAs and 0.4mm pitch WL-CSPs, except that the latter may be assembled without the use of solder paste. Very different considerations apply to flip chip and MLF/QFN/LGA assembly for which separate process guides are provided.
Assembly cannot be viewed independently of quality and reliability requirements and this document offers critical comments and recommendations pertaining to thermal cycle testing.