Defect Classification
Physical separation of a copper terminal area from the underlying resin-glass substrate of a printed circuit board occurs when adhesive strength fails under thermal or mechanical stress. This condition, known as pad delamination, represents a major structural failure that often renders the entire board assembly unusable. The defect typically becomes apparent during soldering or rework phases where prolonged localized heat destroys the cured resin bond.
Because the detached pad can no longer support component leads, electrical continuity is easily compromised.
Thermal Cause
Excessive thermal dwell time during manual soldering destroys the epoxy matrix that binds the copper foil to the laminate. Applying a soldering iron to a pad for too long exceeds the glass transition temperature of the resin, leading to rapid degradation. This localized overheating causes the copper to lift.
Prevention Protocol
Controlling the duration and temperature of thermal operations remains the primary defense against this type of circuit board damage. Manufacturing facilities enforce strict limits on soldering iron contact times and mandate the use of preheaters to reduce the required thermal gradient. Operators use specialized rework profiles that distribute heat evenly rather than concentrating it on a single point.
Designing larger pads and incorporating thermal relief connections also help dissipate heat quickly into surrounding copper planes. Implementing these controlled processes prevents adhesive failure and preserves the physical integrity of the circuit board assembly.
