Manufacturable MEMS microcolumn

This paper reports a MEMS-based microassembly process to manufacture electrostatic electron-beam microcolumns using MEMS connectors and sockets. Different microcolumn components, including deflectors, lens elements, and apertures, are fabricated on a highly doped 50 μm thick SOI (Silicon-on-Insulator) wafer. The components are fabricated using a single silicon device layer. These components with compliant connectors are then assembled onto compliant MEMS sockets fabricated on the same wafer using MEMS NanoEffectors™ and automated assembly. The self-aligning nature of MEMS sockets yields sub-micron lateral alignment and less than 0.18° angular misalignment using two connectors. The lowest measured resonant frequency is 501 Hz in a lens component with two connectors. The angular misalignment and resonance frequency depend on the number of connectors in a component. The footprint of the microcolumn is less than 1 cm2. The microcolumn is designed to achieve a beam diameter of 30 nm with beam energy of 1 keV at currents of 5-10 nA and an 80 μm field of view (FOV) with a doubling of beam diameter at the field edges. We have successfully built two prototype microcolumns that we are currently testing.