Highly Accurate Grating Reference Fabricated by EB Cell Projection Lithography

Abstract

100-nm pitch size silicon grating pattern for calibration reference of electron-beam (EB) metrology systems was achieved. Grating patterns with pitch sizes of 240, 200, 160, and 100-nm in the x and y directions were delineated by EB cell projection writing system using grating stencil mask and these resist patterns were transferred in silicon substrate by dry etching. The pitch size error in the x and y directions was within 1 nm and the uniformity in 1.8×1.8-mm chip was under 3 nm within 3σ. More accurate or convenient calibration of the critical-dimension scanning electron microscope are expected compared with conventional calibration using 240-nm pitch reference grating fabricated by laser-interferometer lithography and anisotropic chemical etching.