Use of Surface Haze for Evaluation of Photoresist Residue Removal Efficiency

A new method for the fast evaluation of photoresist residue removal efficiency is discussed in this paper. In this method “haze” which is the low-frequency component of the background signal of a light scattering instrument is mapped over the entire wafer. Since the background signal is sensitive to any kind of surface anomaly, it can be used as a metrology for any kind of surface roughness or residues. The goal of this paper is to devise a fast and cheap screening method for photoresist residue removal efficiency. Using this method we show that cleaning solutions can be easily screened for their residue removal efficiencies based on the haze signal of the light scattering instrument.