1. 1 QUARTERLY TECHNICAL PROGRESS REVIEW TASK TITLE:Reliability of Pb-free solder alloy study SUBTITLE:Hand soldering process of Sn/Ag alloy QUARTER:4 FY02 CENTER:GSFC PROGRAM AREA:NEPP/EPAC TASK MANAGER at GSFC:Harry Shaw and Jong Kadesch FY02 FUNDING:$40K

2. 2 TASK DESCRIPTION Reliability of Board Level Pb-free Solder joints  Compare reliability of interconnection between the conventional eutectic Sn/Pb solder vs. Pb-free solder alloy. The choice of Pb- free alloy is Sn/Ag. GSFC is evaluating the solder joints using hand-soldering process. JPL is evaluating the solder joints using reflow soldering process.

3. 3 GOALS/OBJECTIVES Reliability of Board Level Pb-free Solder joints Identify a candidate of Pb-free alloys based on a literature search Validate Hand-soldering assembly process: soldering process, usage of flux, selection of soldering guns temp. Compare the solder joints between Sn/Pb solder vs. Pb-free solder alloys: optical solder joint comparison after cross-section.

4. 4 DELIVERABLES Reliability of Board Level Pb-free Solder joints  Presentation slides that summarize the soldering process comparison between Sn/Pb and Sn/Ag. Also include comparison of solder joint in appearance between two alloys and cross-section microstructure of solder joint.

5. 5 SCHEDULE Reliability of Board Level Pb-free Solder joints Major Milestone Q1 Q2 Q3 Q4 Identify and selection of Pb-free solder alloy Procurement of solder alloy, components, and boards Assembly process - hand-soldering of mounting components on the board The assembled boards are subjected to the environmental testing and cross-section specimen. Prepare technical report for the test result.

6. 6 BUDGET/WORKFORCE Reliability of Board Level Pb-free Solder joints

7. 7 MAJOR ACCOMPLISHMENTS THIS QUARTER Reliability of Board Level Pb-free Solder joints  Optical images of cross-sectional analysis of:  63Pb/37Sn solder on tin plated boards  97Sn/3Ag solder on ENIG boards  Preparing final presentation slides  Optical images of cross-sectional analysis of:  63Pb/37Sn solder on tin plated boards  97Sn/3Ag solder on ENIG boards  Preparing final presentation slides

8. 8 METRICS Reliability of Board Level Pb-free Solder joints

9. 9 PLANS FOR NEXT QUARTER Reliability of Board Level Pb-free Solder joints  2nd board assembly for temperature cycles  Selection of temperature cycle oven  Starting temperature cycles between -55 °C and 125 °C  2nd board assembly for temperature cycles  Selection of temperature cycle oven  Starting temperature cycles between -55 °C and 125 °C

10. 10 PROBLEMS AND CONCERNS Reliability of Board Level Pb-free Solder joints  None