Exposing a pattern multiple times improves line-edge roughness, CD uniformity, and resolution. Shifting the fields and/or subfields between the exposures additionally reduces field/subfield stitching issues. In standard multipass (2, 4, or 9 passes), the price to pay for the improved lithographic quality is exposure time and a more complex data preparation.
BEAMER makes multipass simple by automating data preparation (the user just needs to select the number of passes and set the desired field shift/subfield shift). BEAMER generates a single machine file with the overlaying field positions.
To further mitigate the throughput impact, it is possible to apply multipass to selected parts of the layout (layer specific multipass) or apply different number of passes to different doses (dose dependent multipass). This helps to maintain throughput and still get the advantage of multipass in critical features.