The Role of High Temperature Treatments in Stress Release and Defect Reduction

摘要

In this work we discuss an original analysis about a method to reduce the dislocation density in the devices that use the Shallow Trench Isolation (STI). It is well known that a high mechanical stress in silicon combined with an amorphizing implantation damage can generate many dislocations. So we propose to release the mechanical stress in silicon before implanting. A high temperature treatment indeed can trigger the viscous behaviour of the filling oxide inducing the relaxation of the stress field in silicon. For the first time a systematic study of the effect of different furnace and RTP annealings in the stress relaxation was done by Raman measurements. Different temperatures (from 300℃ to 1100℃) and different durations (from few seconds to one hour) were explored and the experimental results were compared with the numerical simulation with a good agreement. Finally we study the effect of the most promising annealings selected by Raman in a complete process flow.