EPL Reticle Technology

摘要

Nikon, in collaboration with IBM, has been developing EB stepper, which is the electron beam projection lithography (EPL) system for 70 nm node generation and below. As the standard reticle for EB stepper (EB reticle), the scattering silicon stencil type is used to obtain highest performance. The EB reticle has thin silicon membranes of thickness 2 μm and membrane size 1.13 mm square with stencil opening patterns, which are supported by a grid-grillage structure. The development of the EB reticle is one of key issues in the EB stepper development. We had accomplished 76mm reticle development using silicon-on-insulator (SOI) wafer with a stress-controlled membranes (less than 10 MPa). Now we are in the 200 mm reticle development phase. We have curried out experiments in cleaning, inspection and repair for the EB reticle, which are very important issues for the EB reticle fabrication, we showed possibilities of Ar aerosol cleaning, a reticle repair using Focused Ion Beam (FIB), pattern defect inspection with DUV microscope and so on.