BGA Package Level Failures Due to Contamination Available to Purchase

Two instances of BGA package level failures were identified during in-circuit electrical test. The electrical opens occurred as a result of contamination issues originating at the board supplier. Analytical techniques including optical inspection, SEM/EDS, Raman and FTIR were key in identifying photoresist on the board surface in the first case study and nickel carbonate contamination on the board surface in the second case study. In the first case study, resolution was achieved with a Plasma etch process. In the second case study, CCAs were cleaned with a wet chemical etch process formulated specifically to attack the nickel carbonate.