Simulating the Residual Layer Thickness in Roll-to-Plate Nanoimprinting with Tensioned Webs

Abstract

Roll-to-plate nanoimprinting with flexible stamps is a fabrication method to pattern large-area substrates with micro- and nanotextures. The imprint consists of the preferred texture on top of a residual layer, of which the thickness and uniformity is critical for many applications. In this work, a numerical model is developed to predict the residual layer thickness (RLT) as a function of the imprint parameters. The model is based on elastohydrodynamic lubrication (EHL) theory, which combines lubrication theory for the pressure build-up in the resin film, with linear elasticity theory for the elastic deformation of the roller material. The model is extended with inextensible cylindrical shell theory to capture the effect of the flexible stamp, which is treated as a tensioned web. The results show that an increase in the tension of the web increases the effective stiffness of the roller, resulting in a reduction in the RLT. The numerical results are validated with layer height measurements from flat layer imprints. It is shown that the simulated minimum layer height corresponds very well with the experimental results for a wide range of resin viscosities, imprint velocities, and imprint loads.

Elastohydrodynamic lubrication of soft-layered rollers and tensioned webs in roll-to-plate nanoimprinting

“…The first two datasets originate from previous work. 19 The experimental results are reused in this study. These imprints are performed for a variation of imprint velocity and imprint load and various in-house-developed resins are used.…”

“…This function is often used in (elasto)hydrodynamic lubrication models as a mass-conserving cavitation algorithm, 19,38 with the film pressure and the mass fraction as dependent variables. In the present study, the Fischer-Burmeister function will reveal the occurrence of contact between the tensioned web and the roller.…”

“…Reproduced with permission from. 19 Roll-to-plate nanoimprint system. implementation of the elastic deformation and contact mechanics of tensioned webs in an EHL system, and the application of this theory in a roll-to-plate nanoimprint process.…”

Emerging low-cost, large-scale photonic platforms with soft lithography and self-assembly

“…Reprinted with permission from Ref. [47], copyright 2022, Multidisciplinary Digital Publishing Institute.…”

“…R2P NIL follows a process similar to that of R2R NIL, except that the patterning roller transfers the patterns to the substrate [Fig. 2(b), iii] [47] . Roller-based methods have realized sub-100 nm features; however, the fabrication of sub-50 nm nanostructures is challenging because of the requirement of precise contact angle control between the resist and substrate [48] .…”