Multielectron beam blanking aperture array system SYNAPSE-2000

TLDR

A blanking aperture array with 1024 25‑µm apertures on a 20‑µm Si membrane offers a 1/6 aperture ratio, and techniques such as large convergence semi‑angle, refocusing, and multicolumns reduce Coulomb interaction to increase throughput. The system is designed to provide a volume‑production microelectronic device manufacturing method. The SYNAPSE‑2000 irradiates a 1024‑aperture array with an electron beam, switches each aperture individually via electrodes while raster‑scanning to project patterns onto wafers at a 1:200 reduction, and uses 512 central beams to expose 18.

Abstract

A blanking aperture array (BAA) has 1024, 25-μm-square apertures and blanking electrodes on a 20-μm-thick Si membrane with a total aperture ratio of 1/6. These apertures are irradiated with an electron beam, and the electrons passing through the apertures are projected onto a wafer surface in a reduction ratio of about 1 to 200. A signal applied to each blanking electrode turns each beam on and off individually while raster-scanning the electron flux with a deflector; thereby the desired pattern on the wafer can be drawn. The SYNAPSE-2000 system uses 512 beams in the center of a BAA and exposes 18 8 in. wafers per hour using a single BAA column. Large convergence semiangle, refocusing, and multicolumns are effective measures to reduce Coulomb interaction and to accomplish higher throughput. This system provides a volume-production microelectronic device manufacturing method.