Investigations on brittle fracture of BGA assemblies on electroless nickel/immerson gold surface finishes

Producers and users of plastic ball grid array packages (PBGA's) have repor ted unexpected solder joint failures at the nickel solder alloy interface f or certain nickel gold final finishes on the PC-board side of a BGA-assembl y. The problem is commonly referred to as "BGA-fracture" or brittle fractur e". In late 1997, the problem became rather urgent and ITRI (Interconnect T echnology Research Institute) formed a team to investigate. Various users a nd suppliers have continued their own investigations as well. Described bel ow is an update for this BGA study covering Atotech's own investigations as well as the ITRI evaluation of the Atotech process.