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Abstract

In a method of manufacturing a photo mask, a resist layer is formed over a mask blank, which includes a mask substrate, a phase shift layer disposed on the mask substrate and a light blocking layer disposed on the phase shift layer. A resist pattern is formed by using a lithographic operation. The light blocking layer is patterned by using the resist pattern as an etching mask. The phase shift layer is patterned by using the patterned light blocking layer as an etching mask. A border region of the mask substrate is covered with an etching hard cover, while a pattern region of the mask substrate is opened. The patterned light blocking layer in the pattern region is patterned through the opening of the etching hard cover. A photo-etching operation is performed on the pattern region to remove residues of the light blocking layer.

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First Claim