Study and Measurement of Micro-Scale Bonding Strength in Vertical Direction

A new way to evaluate the strength of micro-scale bonding is developed by using a silicon cantilever beam bonded on the substrate by a small anchor. The central concept is that the bonding area will be fractured when a certain vertical force is loaded on it, and this force can be used as a “standard”. This test is easy to be carried out. It also can be used in in-situ bonding quality monitoring in MEMS fabrication. Edge effect, the length of the bonding area partly determines the bonding strength, is found in micro-scale bonding. The coefficients of the edge effect, which determine the bonding strength at the interface of the bonding are, are calculated. Designers can use the equations and the coefficients to design the bonding areas according to the requirement of bonding strength for their devices or the appropriate test structures for the bonding quality in-situ monitoring.