Alpha® Blog

Head in Pillow An Easily Missed and Costly Soldering Defect

This frustrating failure mode has increased in frequency when the transition to lead-free soldering accelerated.  The essence of a head-in-pillow (HIP) defect is the incomplete coalescence of a BGA sphere and a solder paste deposit, resulting in a failed solder joint.  This defect looks like a small head resting on a pillow, and it is often missed during inspection.  The biggest issue with the HIP defect is that there is an electrical contact between the BGA component I/O and the printed circuit pad/solder paste deposit, so circuit testing will not detect the flaw.  The circuit will likely open after exposure to thermal cycling or vibration or drop shock after the device has been put in use.

Tough Enough Electronics and Solder Materials

Customer demands are driving electronics assemblers and OEMs to develop more robust electronic devices.  Terms like¹ Shockproof, Waterproof, Freezeproof and Dustproof have significant impact on the materials of construction to be considered particularly when designing mobile consumer electronics.  As consumers’ demands have evolved and the electronic OEMs continue to pursue sustainable sources of differentiation, “tough electronics’” is becoming an increasing part of the Assembly Electronic lexicon.

Alpha Solder Paste Addresses Head in Pillow Defects

Head-in-pillow defects, or incomplete coalescence of BGA sphere and solder paste deposit, is a failure mode that has seen increased frequency since the transition to lead-free soldering.