Production reliability improves through compatible finishes, controlled paste printing, stable reflow, suitable joint geometry, cleanliness, and feedback from inspection and reliability data.
Thermal cycling accelerates fatigue caused by repeated expansion and contraction. Test range, dwell time, ramp rate, sample design, monitoring, and failure criteria must represent the application.
Cracks may result from thermal-expansion mismatch, brittle intermetallic layers, voiding, vibration, board flexure, or handling. Fracture location and morphology help identify the dominant cause.
A solder joint provides electrical, thermal, and mechanical connection throughout product life. Reliability depends on alloy, intermetallic growth, geometry, pad design, assembly conditions, and service stress.