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Nano-Impression Lithography (NIL) has been demonstrated to produce nano features on webs that have value to society. Such demonstrations have largely been the result of NIL processes that involve the discrete stamping of a mold with nano-impressions into a thermoplastic web or a web coated with resin that is cured during the imprint process. To scale NIL to large area products which can be produced economically requires the imprinting to occur on roll-to-roll (R2R) process machines. Nip mechanics is a topic which has been explored in relation to drive nips and winding nips in R2R machines. Nip rollers will be needed to imprint webs at production speeds to ensure mold filling on an imprint roller. The objective of this paper is to demonstrate while the nip roller is required that it can also induce imperfections in the imprinted nano-features. Successful imprinting will require nip loads sufficient to fill the imprint mold and then addressing the nip mechanics which can induce shear and slip that could destroy the nano-features. The objective is to demonstrate through the study of nip mechanics that this shear and slip can be inhibited through the selection of nip materials and tension control of the web entering and exiting the nipped imprint roller.
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EFFECT OF THE PROCESSING AND TRANSPORT PARAMETERS ON MOLD FILLING IN ROLL-TO-ROLL NANOIMPRINT LITHOGRAPHY
Based on a model developed for the roll-to-roll imprinting process, this paper describes the relative importance of the processing, material properties, and transport parameters in Roll-to-Roll Nanoimprint Lithography (R2RNIL). In particular, the model is utilized to investigate the effect of web speed, fluid film thickness, viscosity, stress relaxation time, mold pattern geometry and size on mold filling. Based on a typical imprint roller configuration, kinematic analysis, and the conservation laws from classical mechanics, the behavior of the squeezing of a viscoelastic fluid film into a rigid mold cavity is described. Further, the effect of web speed, fluid film thickness and key rheological parameters, namely the Weissenberg and Deborah numbers, are discussed. These dimensionless numbers are typically employed to quantify viscoelastic effects in fluid flow problems. The effect of other scale-sensitive and geometric parameters, such as the capillary number and pattern width-to-height ratio, on the imprint process is also discussed. Numerical simulations are provided to corroborate the discussions and to quantify the relative importance of the parameters.
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- Award ID(s):
- 1635636
- PAR ID:
- 10110996
- Date Published:
- Journal Name:
- Proceedings of the Fifteenth International Conference on Web Handling
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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