Analysis of surface roughness of critical‐dimension structures using spectroscopic ellipsometry

As critical dimension of integrated‐circuits shrink to 100 nm and below, observation of critical dimension roughness will become increasingly important. In this article, we analyze roughness of grating structure that fabricated on a Si wafer using standard photolithography, and characterize roughness of CD by rigorous coupled‐wave analysis and effective medium approximation method with spectroscopic ellipsometry.