Effects of Cleavage on Local Cross-Sectional Stress Distribution in Trench Isolation Structure

Abstract

We have taken polarized micro-Raman spectra around the cleaved (011) cross section of a trench embedded in the (100) surface of a silicon substrate and found that the cleavage greatly affects the local cross-sectional stress distribution. That is, the stress distribution obtained from Raman measurements on the cleaved surface differs from the original stress distribution before cleavage. We found that a three-dimensional stress simulation based on the elastic model using specific boundary conditions is useful in explaining these cleavage effects and estimating the local cross-sectional stress distribution before cleavage. We describe the change in distribution and direction of each of stress component caused by the cleavage effects in a trench isolation structure. Further, we show that the three normal stress components are important for analyzing the stress distribution obtained from Raman spectra measured on the cleaved cross section of the trench.