NEMI Lead-Free Assembly Project: Comparison Between PbSn and SnAgCu Reliability and Microstructures
C A. Handwerker, J Bath, E -. Benedetto, E -. Bradley, R -. Gedney, Thomas A. Siewert, P Snugovsky, J -. Sohn
The National Electronics Manufacturing Initiative (NEMI) Lead-Free Assembly Project had the following priorities:--to down-select an alloy from the SnAgCu families to be recommended as the main standard lead-free solder;--to demonstrate production-ready parts, materials and processes for lead-free soldering printed wiring board (PWB) assemblies, with an eye to total lead elimination by 2004;--to cooperate with component, board and equipment manufacturers to allow for the smooth transition to components with higher exposure temperature limits of around 260 degrees C; and--to develop criteria for the industry to evaluate lead-free processes and reliability in order to assist industry with timely implementation of lead-free assemblies.This article presents qualitative thermal cycling results for all the components and alloy combinations tested and provides a quantitative comparison of the failure data and microstructures for the CSP169 components for NEMI tin-silver-copper alloy, eutectic tin-lead, and a mixed tin-silver-copper paste with Pb-containing surface finish.
failure analysis, lead free assembly, lead free solder, NEMI, solder joints, solder reliability
, Bath, J.
, Benedetto, E.
, Bradley, E.
, Gedney, R.
, Siewert, T.
, Snugovsky, P.
and Sohn, J.
NEMI Lead-Free Assembly Project: Comparison Between PbSn and SnAgCu Reliability and Microstructures, SMTAI, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=853288
(Accessed December 6, 2023)