he bonding mechanism for a silver-lead borate glass adhesive, used as a die bonding material in microelectronics packaging, was investigated. Silicon dies were bonded to alumina substrates with the glass adhesive, thermally cured and then sectioned, polished and analyzed. The diffusion of silicon from the die was found to be important in the development of the bond. Adhesion between the silver glass and the silicon die was found to be achieved via a glass network structure that starts at the silicon dioxide film on the die back side. Bonding between silver glass and the ceramic substrate was found to be mechanical in nature.