Measurements of the solder joint
thicknesses at T0 were acceptable for both the 100μm and 200μm overhang units.
Cross-section images of the units on the
PCBs showed partial fillets and low to no side-wetting angles for both the 100μm and 200μm
overhang.
All units for both the 100μm and 200μm
overhang passed temperature cycle BLR testing well beyond 1000 cycles without
failure.
Gross anomalies were not witnessed in the
solder joint fillets, even after 3000 cycles of temperature cycle BLR testing, for the
200μm overhang. Voiding and cracking is not expected to cause an electrical or mechanical
failure.