Wafer-Scale Self-Aligned Bilayer Hole Mold Fabrication and Pattern Replication via Nanoimprint Lithography

Abstract

We present a wafer-scale fabrication strategy for three-dimensional (3D) bilayer high–aspect-ratio patterns based on nanoimprint lithography (NIL). The process integrates laser direct-writing grayscale lithography for precise definition of bilayer profiles, followed by two sequential cycles of pattern transfer into a chromium (Cr) hard mask and deep reactive ion etching (DRIE), thereby forming self-aligned 3D patterns on silicon. A flexible polydimethylsiloxane (PDMS) mold replicated from the etched silicon mold enables high-fidelity duplication of the 3D features through ultraviolet nanoimprint lithography (UV-NIL). This approach offers outstanding design flexibility and precise morphological control. Combining process stability, structural precision, and versatility, this approach establishes a reliable route for nanoimprint fabrication of multilayer high–aspect-ratio 3D structures. [2026-0038]