Assembly and Application Specific Methodology to Determine Accelerated Temperature Cycling Requirements for Pb-free Solder Joint Reliability

An assembly-and application-specific methodology is proposed to address the issue of accelerated temperature cycling test requirements for solder joint reliability. This is accomplished by first determining the amount of solder damage that is expected to accumulate in the field over a specified period of time from power cycles (both on/off cycles and mini cycles), and then designing ATC tests to generate the equivalent amount of damage. By equating the damage from the field to that from the tests, the number of ATC cycles can be determined. A step by step procedure is provided to guide the designer in the initial concept stage to design for reliability. An example is provided to highlight the differences between the proposed methodology and traditional correlation models.