One of the primary concerns in the industry today is whether converting to a lead free process from tin/lead will have an impact on the reliability of the assembly. Much testing has been performed in the last 10 years on lead free joints in anticipation of the potential switch by the industry but there are still concerns about the applicability of the results. Most of the testing has been to procedures developed over time for tin/lead alloys and the issue is whether there will be the same correlation between test results and actual product life cycle of lead free products in the field. As reliability is a complex issue, and not just thermal cycling, a number of tests were performed to attempt to simulate the environment in use.

JG-PP is partnering with the DoD's JCAA on a project to generate critical reliability data on circuit cards manufactured and reworked with lead-free and eutectic tin-lead solders for military and space applications. The testing includes vibration, thermal shock, HALT testing, salt fog, temperature/humidity, thermal cycling at multiple ranges and hand solder repair with mixed alloys with cross sectioning and thermal cycling. Successful completion of this project will provide baseline data for use in the eventual qualification of lead free solder in high reliability systems.

Alloys included in the testing regime are Sn63Pb, SN100C and SAC305. Currently, data from these completed tests is being analysed for inclusion in the projects Joint Test Report, targetted for publication in February 2006. The preliminary data and test results from Lead Free Solder Project Number: S-01-EM-026 can be viewed here.

We have prepared a CD containing the bulk of this reliabilty data, a free copy of which is available by contacting Ron Gow or Kirsty Mathieson at DKL Metals.

Bob Willis, SMART Group Technical Director, has been running the Lead Free Experience in conjunction with LEADOUT for the last 3 years and a copy of the Lead-Free Hands-On Experience 3 report based on a range of real life tests conducted during NEPCON 2005 is now available for free by simply visiting www.smartgroup.org and downloading the appropriate file.