A comparative study of air cushion and roll-to-plate pressing in wafer-level nanoimprint lithography

Nanoimprint lithography (NIL) has recently regained significant industrial momentum, driven by the burgeoning demand for high-resolution optical components, AR/VR devices, and advanced semiconductor fabrication. Among current wafer-level NIL strategies, Air Cushion Press (ACP) and Roll-to-Plate Press (R2P) represent two predominant mechanical approaches. This study provides a comprehensive comparative analysis of ACP and R2P to evaluate their efficacy in high-volume wafer manufacturing. Our findings demonstrate that the vacuum-assisted environment in ACP effectively mitigates air entrapment, enabling defect-free imprinting with a rapid cycle time of approximately one minute. Conversely, the R2P process, typically operated under atmospheric conditions, necessitates a protracted bonding phase-often lasting tens of minutes-to evacuate trapped air between the mold and the substrate. Furthermore, ACP achieves superior uniformity in both imprinting pressure and residual layer thickness (RLT), which is critical for maintaining pattern fidelity during subsequent etching processes. While the flexible molds used in both methods are prone to gradual deformation and feature distortion over repeated cycles, the extent of such degradation is significantly lower in ACP than in R2P. While R2P offers a cost-effective solution for large-area patterning on flexible substrates where post-etching is not required, ACP demonstrates clear technical superiority in throughput, uniformity, and precision for high-end wafer-level NIL applications.