W-CMOS Blanking Device for Projection Multi-Beam Lithography

摘要

As the designs of future mask nodes become more and more complex the corresponding pattern writing times will rise significantly when using single beam writing tools. Projection multi-beam lithography [1] is one promising technology to enhance the throughput compared to state of the art VSB pattern generators.rnOne key component of the projection multi-beam tool is an Aperture Plate System (APS) to form and switch thousands of individual beamlets. In our present setup a highly parallel beam is divided into 43,008 individual beamlets by a Si-aperture-plate. These micrometer sized beams pass through larger openings in a blanking-plate and are individually switched on and off by applying a voltage to blanking-electrodes which are placed around the blanking-plate openings. A charged particle 200x reduction optics demagnifies the beamlet array to the substrate. The switched off beams are filtered out in the projection optics so that only the beams which are unaffected by the blanking-plate are projected to the substrate with 200x reduction.rnThe blanking-plate is basically a CMOS device for handling the writing data. In our work the blanking-electrodes are fabricated using CMOS compatible add on processes like SiO_2-etching or metal deposition and structuring. A new approach is the implementation of buried tungsten electrodes for beam blanking.