2008-Snugovsky-SAC-Whiskers

More documents

Recommendations

Info

Nitrogen in Solder • N is present in 20 – Corroded interdendritic spaces and – In the Sn matrix as well – Bulk solder and – Hillocks and whiskers • The N peak is more pronounced using lower voltage, but still detectable under 20 keV 5keV Whisker SEM, 1,800X SEM, 18,000X 20keV
Virgin Components, Ion Chromatography • Virgin devices with the Alloy 42 lead-frame material 21 – Created whiskers - “bad” – Did not grow whiskers - “good” • Bad – are more contaminated than their counterparts – Good ID Bad Good – Chloride - 5X; Fluoride - 3X; Sodium - 3x; Calcium - 2x; Potassium - ~ 2x – No significant difference in nitrate and ammonium Anion Concentration, µg/in2 F - 1.7 0.5 Cl - 5.1 1.0 NO 3 0.6 0.9 SO 4 -2 1.8 1.5 The total level of anions and cations: Bad - 25.4 µg/in2 above acceptable levels Good - 11.2 µg/in2 close to accepted limit Total 9.3 3.9 ID Bad RT Good RT Bad 80°C Good 80°C Cation Concentration, µg/in2 Na + 2.7 2.8 6.9 2.2 NH 4 + 0.0 0.0 0.3 0.3 K + 2.8 2.0 6.8 3.9 Ca 2+ 2.7 2.9 2.1 0.9 Total 8.2 7.7 16.1 7.3
Page 1 and 2: Whisker Growth on SAC Solder Joints
Page 3 and 4: Whisker growth from lead-free solde
Page 5 and 6: Visual and SEM Inspection of Solder
Page 7 and 8: Visual and SEM Inspection of Solder
Page 9 and 10: Cross-section Analyses of Solder Jo
Page 11 and 12: Hillock Microstructure (cont.) •
Page 13 and 14: Inter-granular Corrosion and Lead/S
Page 15 and 16: Inter-granular Corrosion and Lead/S
Page 17 and 18: Details on Protrusions with Irregul
Page 19: Details on Protrusions with Irregul
Page 23 and 24: Virgin Components, Plating Quality
Page 25 and 26: Virgin Components, Composition •
Page 27 and 28: Conclusions Precise cross-sectionin
Page 29 and 30: Conclusions (cont.) • There is no
Page 31: 31 Thank you

2008-Snugovsky-SAC-Whiskers

Create successful ePaper yourself

Delete template?

Save as template?