Solder joint reliability is defined as the ability of your product’s solder joints to function under given conditions and for a specified period of time without exceeding acceptable failure levels.
Whether you are trying to implement a new solder type or new component types, solder joint reliability testing is essential in providing confidence that your product will perform within its intended operating limits. The results from different test programs can be compared to provide an understanding of design requirements for adequate reliability. This provides you with useful technical information for future designs, saving you time and money.
Thermal Cycling is the most common method of testing Solder Joint Reliability. Common test specifications include:
1) JEDEC Standard JESD22-A104 Thermal Cycling, or
2) IPC 9701 Performance Test Methods and Qualification Requirements for Surface Mount Solder Attachments
Thermal Cycling is usually performed at a transition rate of less than or equal to 20C per minute (usually 10 to 14C per minute) to avoid thermal shock with 1-3 cycles per hour. Per IPC-9701, temperature extremes are based on the product category with the low temperature usually 25C below the glass transition temperature (Tg) of the printed circuit board material. The electrical resistance is continuously monitored during testing using data loggers. Typically, the failure definition would be an increase of 20% above the nominal resistance. Testing is continued until 63% of failures occur to characterize the failure distribution. After failure detection, failure Analysis (including cross sections, SEM/EDS, X-RAY, dye and pry, etc.) is utilized to find the location and type of failure.
Representative temperature profile for thermal cycle test conditions.