Combined capillary force and step and flash lithography

The combination of a key element of soft lithography, namely the elastomeric stamp, with the operation principle of step and flash imprint lithography results in a moulding procedure allowing high throughput and remarkable operational simplicity. 100 nm scale dense features can be fabricated via in situ polymerization of a polyurethane fluid, simultaneous to the capillary penetration into the recessed regions of high-resolution elastomeric elements. Excellent pattern definition has been obtained for features down to 200 nm, with aspect ratio of around unity over areas of the order of cm2. The physical principles of the fluidic motion within the sub-µm channels are also discussed, to estimate the maximum aspect ratio achievable before the complete curing of the employed photopolymer.