Load induced stresses and plastic deformation in 450mm silicon wafers

The authors present the physical basis for estimation of gravitational constraints in 450mm silicon wafers subjected to high temperature processes. They have identified and quantified the relevant phenomena to predict the mechanical behavior of very large silicon wafers horizontally stacked and ring- or pointlike supported in a vertical-type furnace. It is shown that load induced stress at the supports increases directly proportional with increasing wafer diameter, although the weight of the wafer increases with the square of diameter. The results allow the optimization for a defect-free high temperature treatment of 450mm wafer used for leading edge device fabrication in future.