Nanometer metal line fabrication using a ZEP520∕50K PMMA bilayer resist by e-beam lithography

In this work, we propose a bilayer resist system with 50K poly methylmethacrylate as the bottom layer and ZEP520 as the top layer for lift-off process. By making use of the different dissolution rates in the rinser for the top and bottom layers, it is possible to create an overhang resist pattern suitable for lift-off. In this specific study, a set of process parameters have been optimized to fabricate Cr metal lines with a width of about 70nm. The process has been used to fabricate nanometer scale magnetic sensors for data storage applications.

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