From Exploration to Exploitation: Role of Gender and Strategic Choices of Top Management Teams in Start-up growth and Performance

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Reliability of printed circuit boards containing lead-free solder in aggressive environments

Lead-free solders were never an industry choice until government legislation, their wide spread use is still in its infancy due to long term reliability issues. Nonetheless, one specific family of materials emerged as the favourite to offer technical advantages as well as meeting those legislative requirements. This paper investigates accelerated life behaviour of lead-free solder joints and printed circuit boards using thermal and stress cycling. The aim is to understand better the degradation of these materials in the real operating environment. Whilst corrosion and debris deposits have been found, no significant evidence has been obtained for tin whiskering. EDX analysis has shown high concentrations of elements thought to arise from the packaging material. The thermal cycling test has presented an aggressive environment to the samples supported by microscopic and macroscopic observations of debris and corrosion. However, the electrical behaviour, i.e., the joint resistance, has not significantly degraded

Structural integrity in electronics

With continuing miniaturisation, increased performance demands and the requirement to remove lead from solder alloys, the challenges to structural integrity and reliability of electronic equipment are substantial and increasing. This paper outlines typical features in electronic equipment of which the structural integrity community may be generally unaware. Potential failure modes in service are described, and the problems of scale and material characteristics are considered. Progress in the application of fracture mechanics to the life prediction of interconnections is reviewed. The limited evidence available suggests that the crack growth resistance of silver-containing lead-free solders is superior to that of the traditional Sn-37Pb under cycle-controlled conditions but there is no difference when time-dependent conditions prevail. In several respects, it is contended that the electronics sector is faced with challenges at least equivalent to those encountered in gas turbines and nuclear power generation