AES/ESCA/SEM/EDX Studies of Die Bond Materials and Interfaces

The choice of a die bonding material and processes for a microelectronic application, especially of accommodating the large size (up to 400 mils) and high density (up to 200 I/O connections) of VLSI chips, presents a matrix of considerations. They are the material properties, bonding surface characteristics, packaging compatibility and assembly procedures, etc. Above all, the die bond has to meet stringent reliability requirements. Die bonding failures have been reported numerously in the past. Only the failure modes and specu-lated failure mechanisms were documented. The present study uses the Perkin Elmer Auger/ESCA system to study the surface elements and their chemical states on the bonding surface; uses the Cambridge SEM/EDX system to study the failure modes and the cross-sectional profile; and uses the Dupont thermal analysi-s system to determine the physical and/or chemi-cal reactions of the die attach materials. It is the intention to provide a better understanding of the die bonding materials and material/ process related failures, and to help eliminate the problems of hot spots and thermal stressing of the interface caused by void formation.