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Front-end semiconductor lithography demands smaller size of patterns for 9Onm node and beyond, on both Si wafers and photomasks. In dry etching for photomasks, it needs tighter CD uniformity and loading effect. For meeting these demands the advanced NLD (magnetic Neutral Loop Discharge) mask etcher has been developed, because it could operate at lower pressure for reducing loading effect than conventional ICP etchers, due to the magnetic confinement of electron in plasma generationP In the NLD mask etcher, the configuration of plasma source was investigated for better performance and the etching condition was reoptimized for improving selectivity. Consequently, the selectivity of Cr/resist(ZEP-7000) was more than 1.6, compared with 0.95 in the pervious condition.2 And also, the CD uniformity in Cr etching was improved to meet our target 6nm(3 sigma) around O.68Pa. However, in the view ofreducing loading effect, other condition that is lower pressure than O.68Pa and adding Helium (He) showed smaller global loading. Therefore, making a balance of uniformity and loading is necessary to get better performance in mask process. We also propose a basic condition using the advanced NLD mask etcher for dry etching a MoSiON shifter of attenuated PSM in this paper.

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