SAN JOSE – A Lockheed Martin engineer has devised a matrix for gold content and is making the calculator available at no cost. The nonproprietary Excel spreadsheet allows users to plug in solder and gold thickness, plus the pad and component attach geometry, and then calculates the percent-gold, making it simple to determine whether the fillet might encounter gold-embrittlement problems.

Users could also create their own gold thresholds and color schemes.

The Excel spreadsheet it is based on complete mixing and does not encompass intermetallics or diffusion rates and concentration gradients, and provides no reliability guidance.

The spreadsheet was devised by Melissa Lau of Lockheed Martin, and could be modified or created to keep track of questions that might arise over Pb-free, tin concentration or other metals, says Tom Clifford, group leader, advanced packaging at Lockheed Martin.

For feedback and explanations contact Clifford at clifford@lmco.com.

 GOLD CALCULATOR.XLS (80.00 KB)