A novel liquid thermal polymerization resist for nanoimprint lithography with low shrinkage and high flowability

Abstract

A novel liquid thermal polymerization resist was prepared for nanoimprint lithography on flexible plastic substrates. The resist is a mixture of poly(methyl methacrylate) (PMMA), methylmethacrylate (MMA), n-butylacrylate (n-BA), methacrylic acid (MAA) and 2,2′-azobisisobutyronitrile (AIBN). The resist can be imprinted at room temperature with a pressure of 1.2 MPa, and then cured at 95 °C to obtain nano-scaled and micro-scaled patterns. Replications of high-density line and space patterns with resolutions of 50 and 100 nm were obtained on a flexible ITO/PET substrate. The liquid resist has low viscosity, and shows a near-zero residual layer at the bottom of the pattern. Due to the addition of PMMA as the binder, the shrinkage of the resist after curing is only 2.01%.

Solar biosupercapacitor

“…(b) No visual damage on the surface after distortion and bending of the film. Reproduced from[57] with permission from IOP Publishing Ltd.…”

Comparison of monomer and polymer resists in thermal nanoimprint lithography

“…10 The difference may be explained by the fact that the polymerization takes place here at higher temperature allowing a better rearrangement in the material. Such a high shrinkage is a problem for the control of the critical dimensions, but previous studies 5,6 showed that it is possible to reduce this value.…”

Nanoimprint lithography: An old story in modern times? A review

“…108,109 In a similar way, this method can be used with viscous resins, as long as the vapor pressure of the resin at room temperature is low. [110][111][112][113][114][115] Spin coating is also used for the patterning over topography, i.e., for the preparation of the thick solid planarization layer in bi-and multilayer resists. A resist stack used in SFIL typically consists of a Si containing NIL resist ͑called etch barrier or hard mask͒ on top of a functional layer ͑called transfer layer which acts as antireflective coating by absorbing light͒.…”

“…UVcurable NIL materials are composed of a mixture of monomers ͑or prepolymers͒ and a suitable photoinitiator, and often chemicals are added which decrease the effect of radical scavengers on photopolymerization. 6,[111][112][113][114][115][116][117][118][119] Immediately during contact of the stamp with the liquid mixture, filling of the mold starts by capillary forces, which pulls the stamp toward the substrate. Therefore, the general strategy is as follows: Low viscosities are needed both for rapid dispensing and filling of mold cavities.…”