126 Semiconductors: Integrated Circuit Design for Manufacturability
the e-beam tools for a full-delity ILT mask. Superior corner rounding for ILT
was due to the fact that ILT calculates mask geometries based on the required
silicon image, unlike MB OPC, which works from the mask pattern.
3.4.2.4 Mask Manufacturability
An important aspect of 2D DfM and variability reduction is the quality of
the information carrier from the virtual to the real space, i.e., the photomask.
Pattern transfer from design to wafer traditionally uses a two-phase approach:
• Phase 1: Pattern transfer from design to mask, by direct writing on
mask resist with a laser or ebeam tool.
• Phase 2: Pattern transfer from mask to wafer, by exposing the mask
image on the ...