Ceramic chip scale package solder joint reliability

As part of a programme of characterisation of interconnection technologies for computer server products the present investigation was conducted to determine the attachment integrity and long-term reliability of resistor network ceramic Chip Scale Package (CSP) solder joints. Accelerated thermal cycling with electrical continuity monitoring of the solder joints was used to determine reliability. The thermal cycling was combined with metallographic examination of appropriate solder joints to evaluate the failure modes and to corroborate the failure thresholds. The measured reliability for the CSP solder joints was 1,027 thermal cycles. This implied an estimated minimum lifetime of 7.8 years for the product in a worst-case field use. The reliability was virtually unaffected by the solder joint pad size and geometry on the board. All fatigue failed solder joints exhibited similar failure modes.