Dye and Pry of BGA Solder Joints - Cascade Engineering

1 Dye and Pry of BGA Solder Engineering GroupCascade Engineering Services, 185th Ave NE Redmond WA 98052(425) 895-8617 x 564 CPU Failure InvestigationEquipment Used Dye and Pry TechniqueConclusions Majority of failures (cracks from mechanical bend overstress test) observed at Solder -Chip interface Summary of % area cracked at each interface in the area of interestOptical Image with Extended Focal Imaging StitchingSol der- Chi pOkSol der- PCBOkSol der- PCBOkSol der- PCBOkSol der- Chi p~5%Sol der- Chi pOkSol der- PCBOkSol der- PCBOkSol der- PCBOkSol der- PCBOkSol der- Chi p~10%Sol der- PCBOkSol der- PCBOkSol der- PCBOkSol der- Chi p~20%Sol der- PCBOkChipPCBDRAM Failure InvestigationEquipment Used Dye and Pry TechniqueConclusions Interfacial fracture / cracks observed at two locations.

2 Solder -CU-PCB Interface and Solder Chip interface Summary of % area cracked at each interface in the area of interestChipPCBSol der -ch ip~80%Sol der -PCB~50%Sol der -ch ip~5%Sol der -ch ip~50%Sol der -PCB~40%Sol der -PCB~50%Sol der -ch ip~50%Sol der -ch ip~15%Sol der -Chi p~10%Sol der -ch ipDRAM Failure Investigation (Continued)Equipment Used Dye and Pry TechniqueChipPCBI mages show the fracture surface after three point bending of red dye indicates cracks in the area of interestDRAM Failure Investigation (Continued)Equipment Used Dye and Pry TechniqueImages show the fracture surface after three point bending of red dye indicates cracks in the area of interestA Solder joint on the PCB sideA Solder joint on the chip si