Hayes, Soloway, Hennessey, Grossman & Hage, P.C.
Electron-beam cell projection aperture formation method
 The present invention provides an electron-beam cell projection aperture formation method comprising: a step of applying a converged ion beam to a top surface of a substrate so as to be etched to a depth enabling to obtain a sufficient film thickness for absorbing or scattering an electron-beam thereby to form an opening of a desired pattern on the top surface; and a step of uniformly applying the converged ion beam to a back surface of the substrate, excluding a hem portion thereof, so as to be etched to a depth reaching the opening. 
NEC Corporation
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Hiroshi
Yamashita