Gross substrate defects caused by thermal gradients in high temperature furnace processes

High temperature anneals are required for densification of oxide-gap fill shallow trench isolation structures. A major concern in these processes is wafer deformation and substrate damage, which raises reliability concerns. The corresponding defects, like surface particles, seen on the wafer front-side through inline monitoring may not necessarily be indicative of substrate damage. More extensive study and partitioning are needed to characterize and recognize the defect source and mechanism. This case presented in this work is an example of the investigation and sourcing of front-side defects caused by thermal gradients between wafer back side contact points and the hot furnace environment.