All-inorganic thermal nanoimprint process

The authors describe a nanoimprint method for an all-inorganic resist material, aluminum oxide phosphate. The resist is free of organic additives, water-based, environmentally benign and yields dense, amorphous, crack-, and pore-free films after annealing at 300 °C. They achieved macroscopically defect-free imprinted areas of up to 25 cm2, using flexible ethylene tetrafluoroethylene imprint molds. It is shown that, if temperature and pressure are chosen such that the residual solvent in the resist stays liquid during imprinting, macroscopically defect-free imprints can be obtained. Volumetric shrinkage due to postimprint annealing is characterized. The imprinting tests are performed on standard thermal nanoimprint equipment, but the process is believed to be scalable for large-area imprinting.

[1]  U. Gösele,et al.  Mesoscopic ferroelectric cell arrays prepared by imprint lithography , 2003 .

[2]  J. Werner,et al.  Sol-gel coatings for light trapping in crystalline thin film silicon solar cells , 1997 .

[3]  Christophe Peroz,et al.  Glass nanostructures fabricated by soft thermal nanoimprint , 2007 .

[4]  Kyung Min Yoon,et al.  Fabrication of polycrystalline TiO2 nanopatterns by TiO2 sol base imprint lithography , 2009 .

[5]  W. Lukosz,et al.  Embossing technique for fabricating integrated optical components in hard inorganic waveguiding materials. , 1983, Optics letters.

[6]  W. Kim,et al.  Fabrication of ridge waveguides by UV embossing and stamping of sol-gel hybrid materials , 2004 .

[7]  M. McGehee,et al.  Nanostructuring titania by embossing with polymer molds made from anodic alumina templates. , 2005, Nano letters.

[8]  Mihee M. Kim,et al.  Low‐Cost Fabrication of Transparent Hard Replica Molds for Imprinting Lithography , 2009 .

[9]  Patrik Hoffmann,et al.  High‐Resolution Nanoimprinting with a Robust and Reusable Polymer Mold , 2007 .

[10]  Jian Wang,et al.  Large area direct nanoimprinting of SiO2–TiO2 gel gratings for optical applications , 2003 .

[11]  Marc A. Verschuuren,et al.  3D Photonic Structures by Sol-Gel Imprint Lithography , 2007 .

[12]  Christophe Peroz,et al.  Nanoimprint lithography on silica sol-gels: a simple route to sequential patterning. , 2009, Advanced materials.

[13]  M. Hutley,et al.  The Optical Properties of 'Moth Eye' Antireflection Surfaces , 1982 .

[14]  Volker Wittwer,et al.  Antireflective transparent covers for solar devices , 2000 .

[15]  D. Keszler,et al.  Solution-Processed Aluminum Oxide Phosphate Thin-Film Dielectrics , 2007 .

[16]  G. Whitesides,et al.  FABRICATION OF GLASS MICROSTRUCTURES BY MICRO-MOLDING OF SOL-GEL PRECURSORS , 1998 .

[17]  R. Morf,et al.  Submicrometer gratings for solar energy applications. , 1995, Applied optics.