Board level reliability testing of μBGA/sup (R)/ packaging with lead-free solder attachment

Abstract

To maximize the benefit of chip-scale packaging for portable and hand-held electronics, the user must consider efficient and cost effective assembly processing. Factors that an engineer should review before developing the product using CSP may include physical features and construction of the device, environmental limitations, suitable substrate materials and a general understanding attachment methodology. Many of the electronic products being developed using miniature chip-scale package are moving toward lead-free, environmentally safe assembly processes.This paper will review chip-size Flash and RAMBUS memory test device applications utilizing pBGAB package technology, explore alternative solder alloy compositions, furnish recommendations for solder process temperature profiles and present the results from extensive thermal cycle testing, comparing eutectic solder to lead-free solder ball contacts .and attachment materials. IntroductionIndustry specifications establish the specific test methods to evaluate the performance and reliability for CSP attachment. The tests are designed to replicate actual use environments of the electronic assemblies. In addition, it establishes different levels of performance and reliability of the solder attachments of all surface mount devices to rigid, flexible and rigid-flex circuit structures.

Effective Solder for Improved Thermo-Mechanical Reliability of Solder Joints in a Ball Grid Array (BGA) Soldered on Printed Circuit Board (PCB)

“…Because of this premise, the rough fracture surfaces of failed solder joints slide relative to one another during accelerated thermal cycling, producing electrical transients that are characteristic of the short term. [46][47][48][49][50] Failures are defined based on the increase in resistance, 41,[51][52][53][54][55][56][57] resistance thresholds, or electrical discontinuities. 12,[58][59][60][61][62] Four standards are currently in use by the electronics manufacturing industry to specify solder joint failure criteria during reliability and qualification tests of surface mount technology (SMT) solder joints.…”