Open Access Special Issue Article

Mold Fabrication for 3D Dual Damascene Imprinting

SM Saydur Rahman and Bo Cui*

Author Affiliations

Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, N2L3G1, Canada

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Nanoscale Research Letters 2010, 5:545-549  doi:10.1007/s11671-010-9540-2

Published: 30 January 2010

Abstract

Previously, a damascene process based on nanoimprint lithography has been proposed (Schmid G M, et al. in J Vac Sci Technol B 24(3) 1283, 2006) to greatly reduce the fabrication steps of metal interconnection in integrated circuit. For such a process to become a viable technique, a mold having two pattern levels with precise alignment between them must be fabricated first. To this end, this work demonstrates a “self-aligned” fabrication process where the two pattern levels would be perfectly aligned if ignoring the noise during e-beam writing. The process is based on one EBL on a bi-layer resist stack, with the sensitivity for the top layer much higher than that of the bottom layer, which enables separate pattern transfer of the two pattern levels. Using ZEP-520A and poly(dimethylglutarimide) (PMGI) resists, we fabricated pillars having a diameter of 150 nm sitting on ridges having a width of 1.5 μm, which can be used to create via-holes and trenches for IC interconnect by nanoimprint lithography. The current process can also find applications in other areas that require two-level patterning with precise alignment between them.

Keywords:
Nanofabrication; Electron beam lithography; Nanoimprint lithography; Mold; Nanostructure; Resist