NiAu substitution by Sn finish for military applications: a good solution

摘要

For many users, the ramp-up of "X" BGA technology in electronic boards highlights the random risk of reliability problems linked with the NiAu finish widely used for its excellent flatness. These reliability problems known as "skip-plating", "black-pad", "brittle fracture" are sometimes very difficult to detect before releasing the board in the operation field. In consequence, risk can be very costly for the equipment maker. Tin finish is considered as a good NiAu challenger for many reasons, among them the most attractive are flatness, press-fit compatibility, lead free (for the future), low cost, good solder joints properties with all types of packages. This paper deals with how the assessment and qualification of the Sn finish that have been done for Thales applications.