Mask bias effects in e-beam cell projection lithography

We newly developed the mask bias method in electron beam (EB) cell projection lithography to improve the resolution and to increase the throughput. In this method, the open slits of EB mask are shrunk to reduce the ratio of open area in EB mask. This shrinkage decreases the Coulomb interaction effect and the proximity effect. This results that 0.14 micrometer L/S pattern can be resolved even at the maximum shot size (25 micrometer 2 ) and so the writing time of 0.14 micrometer L/S pattern can be reduced by half.