| 摘要 |
A method of forming a rim type of photomask prevents a chrome pattern formed in the 0°-phase shift region of the mask substrate from being irregular and hence, ensures that the border of the 0°-phase shift region has a uniform width. First, a light blocking layer is formed on a quartz substrate. A select portion of the light blocking layer is etched to form a patterned light blocking layer, and the underlying quartz substrate is etched to a predetermined depth to form a 180°-phase shift region. Then, a fluid material layer is formed on the quartz substrate without an electron beam lithography process. The fluid material layer covers a central portion of the patterned light blocking layer and leaves an outer peripheral portion of the patterned light blocking layer exposed. Subsequently, the patterned light blocking layer is etched using the fluid material layer as a mask to form a light blocking pattern and to expose the substrate along a border adjacent the 180°-phase shift region. Finally, the fluid material layer is removed.
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