Effects of Solder Creep on Optical Component Reliability

A study of the reliability of the optical components affected by the creep behavior in soldered joints is described. Using samples which are models of solder joints in optical components, the microscopic creep phenomenon of the soldered joints is observed to exhibit primary followed by secondary creep, as is the case with many other metals. The dispersion of creep-rate data for the tested samples agrees well with the lognormal distribution. The dispersion is almost completely dependent upon the dispersion of the soldered joint areas. The failure rates of optical components for a system's service period are calculated according to the creep behavior. As a result, the optical components assembled by soldering techniques can be confirmed to achieve high reliability.