Barrel Cracks in an Accelerated Failure Mode

摘要

When exposed to thermal cycle testing, copper cracks that develop at an ever-increasing rate in the barrel of plated through holes (PTHs) represent an accelerated failure mode. This is a failure mode where material change plays a major role in how the circuits fail. The damage may have a delayed onset, but once initiated, tend to accelerate until failure as noted by a 10% increase in resistance is complete. Cracks in the barrel of the PTH advance through the metallization and the electrodeposited copper layers, propagating through copper crystals and tra-versing the barrel in a straight, horizontal path.