Mechanism of deep UV photo resist tail on inorganic anti-reflective layer film

As the minimum feature size decreases down to 0.20 mum, a minute pattern deformation can result in serious critical dimension variation. To minimize the critical dimension variation, the interaction of the positive-tone chemical amplification resist with SiOxNy type inorganic anti-reflective layer is investigated. The surface characterization of inorganic anti-reflective layer reveals that Si-NHx(x=0,1,2) and Si-N=O groups are attributed to the cause of the DUV PR footing. Based on the analyses, the technique to reduce the pattern deformation of the chemical amplification resist on inorganic anti-reflective layer is suggested.