| 摘要 |
A photomask blank substrate is selected for use in a process where at least a masking film or a phase shift film is deposited on a top surface of a photomask blank substrate to form a photomask blank, the deposited film is patterned to form a photomask, and the photomask is mounted in an exposure tool. The substrate is selected by simulating a change in shape in the top surface of the substrate, from prior to film deposition thereon to when the photomask is mounted in the exposure tool; determining the shape of the substrate top surface prior to the change that will impart to the top surface a flat shape when the photomask is mounted in the exposure tool; and selecting, as an acceptable substrate, a substrate having this top surface shape. The selected substrate has an optimized top surface shape that improves productivity in photomask fabrication. |
