With EUV Lithography being in production for a couple of years the lithography optimization focuses on two main aspects: improving the productivity (e.g. by lowering the dose to size) and reducing the smallest pitch in the design. This has led to a reassessment of the applicability of contrast/resolution enhancement techniques. Another very important aspect, impacted by dose to size and minimum pitch, is the variability in the lithography which needs to be reduced over time in line with the EPE requirements of the device manufacturing.
We will restrict ourselves on the items which can be observed after exposing on a single scanner and for simple test structures (single layer EPE), thus omitting variability from layer to layer overlay, proximity bias differences between scanners, OPC errors through features and etch effects. It includes global and local CD errors, and global and local placement errors of the structures.
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