CHARGED-PARTICLE-BEAM PROJECTION-EXPOSURE APPARATUS AND METHODS EXHIBITING IMPROVED ALIGNMENT AND REGISTRATION OF PROJECTED PATTERN PORTIONS

Charged-particle-beam projection-exposure apparatus and methods are disclosed that achieve improved pattern-transfer accuracy, especially when using a segmented stencil reticle. To such end, the pattern field of a reticle pattern is divided into multiple exposure units that are individually and sequentially exposed onto corresponding regions on a substrate (e.g., semiconductor wafer). Any exposure units defining a feature surrounding an island region are split into complementary exposure units. Boundaries between adjacent exposure units are placed so as not to cross features or feature portions in the respective exposure units, defined by “white” regions of the reticle. Thus, when images of the exposure units are stitched together on the wafer, improved feature registration, alignment, and linewidth control are achieved.