Dry etching technologies for Cr film

We have investigated Cr film etching mechanism systematically in order to minimize CDU (CD Uniformity). As a result, employing our dry etching system ARESTM with optimized etch process we achieved an excellent CDU(3σ) (0.5nm with etch contribution). Cr film has been widely used not only for the light-shielding film at Cr Binary Mask but also as a hard mask film at even the leading edge photomasks (Hard Mask-PSM (Phase Shift Mask)). In case of used as a hard-mask, this plays very important role to determine etching process accuracy and to achieve the minimal CDU. As LSI downscaling and complication of their pattern layouts, the current dry etch technology faces technical challenges such as the difficulties in CD control and will be not sufficient to meet requirements. In this study, each behavior of Cr etching process at the various process parameters and various pattern layouts are investigated.