Experimental evaluation of anodic bonding process based on the Taguchi analysis of interfacial fracture toughness

Anodic bonding process has been quantitatively evaluated based on the Taguchi analysis of the interfacial fracture toughness, measured at the interface of anodically bonded silicon-glass bimorphs. A new test specimen with a pre-inserted blade has been devised for interfacial fracture toughness measurement. A set of 81 different anodic bonding conditions has been considered and included three different conditions for each of four process parameters: bonding load, bonding temperature, anodic voltage and voltage supply time. The Taguchi method has been used to reduce the number of experiments required for the bonding strength evaluation, thus obtaining nine independent cases out of the 81 possible combinations. The interfacial fracture toughness has been measured for the nine cases in the range of 0.03 similar to 6.12 J/m(2). Among the four process parameters, the bonding temperature causes the most dominant influence to the bonding strength with the influence factor of 67.7%. The influence factors of other process parameters, such as anodic voltage and voltage supply time, bonding load, are evaluated as 18%, 12% and 2.3%, respectively. The maximum bonding strength of 7.23 J/m(2) has been achieved at the bonding temperature of 460 degrees C with the bonding load of 45 gf/cm(2), the applied voltage of 600 V and the voltage supply time of 25 minites. (C) 1999 Elsevier Science S.A. All rights reserved.