Importance

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Abstract

EUV masks and methods of fabrication thereof are described herein. An exemplary method includes receiving an EUV mask having a multilayer structure, a capping layer disposed over the multilayer structure, a patterned absorber layer disposed over the capping layer, and a patterned hard mask disposed over the patterned absorber layer. The method further includes removing the patterned hard mask by performing a first etching process to partially remove the patterned hard mask and performing a second etching process to remove a remainder of the patterned hard mask. The first etching process uses a first etchant, and the second etching process uses a second etchant. The second etchant is different than the first etchant. In some embodiments, the first etchant is a halogen-based plasma (e.g., a Cl₂ plasma), and the second etchant is a halogen-and-oxygen-based plasma (e.g., a Cl₂+O₂ plasma).

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First Claim