Pad Crystal Defect Forming Mechanism And Preventive Action

Along with the increasing of the integrity and scaling down of the feature sizein modern ULSI (Ultra-large scale integrity circuit) manufacturing industry, more andmore challenges are faced for improving the bonding quality and reliability in theassembly process. The pad crystal defect is one major risk for the bonding process.The pad crystal defect is introduced in this paper especially, reviewed the appearanceof pad crystal and analysis the mechanism. There are two major factors which inducedpad crystal. One is high environment humidity; the other is fluorine re sidue on thewafer surface. To reduce the pad crystal suffering risk,3process optimizations areproviding.