Optimal design of an inter-board strain-relief for high-reliability surface mount attachment

The long-term reliability of surface mount (SM) interconnections remains an important issue in many electronics packaging technologies. Strain-reliefs with sufficient compliance can minimize the cyclic loads impressed on SM solder connections during operational temperature excursions, appreciably increasing the margin for long-term attachment reliability. Compliance evaluation was performed for an inter-board strain-relief, or bond-strap, in a commercial Low-Noise Amplifier (LNA) used in various AT&T wireless transmission systems. The bond-strap compliance was optimized, within practical forming and assembly constraints, to provide robust SM interconnection during the expected product service life