The inter metallics you can see are:
Ag3Sn – Needle like structures
Cu6Sn5 – blotchy spots all around solder ball and typically the layer between the ball and the pad(s)
This cross section was taken from a Package on Package components which was thermally cycled from -25 C to 125 C (30 min dwell) for 1000 cycles.
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — “The Secret Culprit in the Theranos Mess”
Wearables — Cereal box to cosplay
Electronics — Counting Pin Numbers
Biohacking — “Doctor Ready to Perform First Human Head Transplant”
No comments yet.
Sorry, the comment form is closed at this time.