Flow behavior at the embossing stage of nanoimprint lithography

Jeong, Jun‐Ho; Choi, Yang‐Kyu; Shin, Young-Jae; Lee, Jaejong; Park, Kyoung-Taik; Lee, Eung-Sug; Lee, Sang-Rok

doi:10.1007/bf02892627

Cited by 62 publications

(53 citation statements)

References 9 publications

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“…Moreover, the purpose of the present study is to explore the applicability of simple models, and this can be limited to simple behaviors in a first stage. For the same reason, and like in many other studies, surface tension is neglected here, although it may play an important role at the nano scale and has been taken into account by Jeong et al (2002) and Rowland et al (2005), among others. A consequence of these assumptions is that the process parameter can be indifferently either the downward velocity V of the mold or the force F applied per unit pattern length, since these two quantities are proportional when the fluid is Newtonian.…”

Section: Problem Statementmentioning

confidence: 99%

“…Nanoimprint lithography can be used to reproduce a variety of patterns, like periodic arrays of pillars or holes with circular or square cross-sections, among others (see Guo, 2004, for examples), but simple lines are very frequently used to demonstrate the technique, as in the pioneering papers by Chou et al (1995Chou et al ( , 1996, and to test models (Jeong et al, 2002;Rowland et al, 2005;Young, 2005, for instance). One advantage of line patterns is the two-dimensional flow involved, which allows the study of a mere cross section.…”

Section: Problem Statementmentioning

confidence: 99%

“…The pattern The polymer is defined as a linear viscous fluid in this study, and its viscosity η is the only material parameter, as in Leveder at al. (2007) or Jeong et al (2002), although power-law viscous fluids were considered in the finite element simulations of Rowland et al (2005) and in the analytical approach of Hsin and Young (2008), among others. Actually, as shown 4 by Schultz et al (2006), for instance, the polymer exhibits shear-thinning above a transition shear rate, but the limitation to a linear behavior may be acceptable for low strain rates.…”

Section: Problem Statementmentioning

confidence: 99%

“…For instance, Schultz et al (2006) adapted this theory to model the flow below an elementary periodic pattern, and Leveder et al (2007) used it in a reverse manner to deduce the polymer viscosity from the applied force. The other approach, which allows especially to overcome the limitation of the lubrication theory to small thickness-to-width aspect ratios below patterns, performs a full numerical simulation of the polymer flow like in Jeong et al (2002), or Rowland et al (2005), for example. These authors put emphasis on polymer flow but did not provide the corresponding imprint force, though, whereas Young (2005) did compute it.…”

Section: Introductionmentioning

confidence: 99%

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Limitations of Simple Flow Models for the Simulation of Nanoimprint

Teyssèdre

Pierre

Régnier

2013

International Polymer Processing

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A quick evaluation of the forces involved in nanoimprint would be very helpful in the prevention of mold deflection. Unfortunately, it is shown here that assuming simplified flows may lead to quite incorrect evaluations of these forces, even for simple periodic patterns and a Newtonian behavior. The mere use of the classical result of the lubrication theory does not account for the range of thickness-to-width ratios that may be involved, especially at the beginning of the process. An improved squeeze model includes this effect, but still underestimates the imprint force. Moreover, finite element simulations demonstrate limitations of two more elaborate models that are found in the literature. These simulations also show that two flow modes can be defined, according to whether or not the polymer touches the mold sidewalls. A deeper analysis of these two modes may help the definition of a more appropriate simplified model in the future.

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Section: Problem Statementmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Limitations of Simple Flow Models for the Simulation of Nanoimprint

Teyssèdre

Pierre

Régnier

2013

International Polymer Processing

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“…Jeong et al, study simulated hot embossing micro/nano-manufacturing with thin films, including the effects of capillary force and width of stamp groove on the flow behavior during embossing. Simulations showed double peak flow for regions of large width, slow printing speeds and with surface tension as a significant factor (Jeong et al, 2002). Macintyre and Thoms developed a method to directly observe the flow of resist arising from NIL.…”

Section: Filling Processmentioning

confidence: 99%

Nanoimprint Lithography

Lan¹,

Ding²

2010

Lithography

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Numerical studies of electrically induced pattern formation by coupling liquid dielectrophoresis and two‐phase flow

et al. 2011

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Electrically induced patterning process, as a novel micro- or nano-structuring approach for fabrication of various micro- or nano-systems, is usually implemented by applying a voltage to an electrode pair consisting of a patterned or non-patterned template and a polymer-coated substrate separated in parallel by an air gap, followed by photo- or thermo-curing of the fluidic and dielectric polymer. The analyses performed so far to characterize this patterning process have been based on linear thermodynamics for a thermally instable thin film perturbed by an electrostatically induced hydraulic pressure. For mathematical simplicity, these analyses were formulated only for a flat template and a flat film surface with infinite planar area, demonstrating the tendency of initial pattern growth on the polymer film, but being unable to visualize the dynamic evolution of micro- or nano-structure growth throughout the patterning process for a real-life template in practical applications. This paper attempts to provide another insight into this patterning process from a viewpoint of liquid dielectrophoresis (L-DEP), by presenting an approach for numerical simulation of the patterning process based on a coupling of L-DEP and two-phase flow theories. First, a numerical analysis has been made for the electrocoalescence of a water droplet with bottom water in silicone oil to benchmark effectiveness of the proposed numerical approach against published experimental observations. More numerical results have then been provided to show effects of some process variables on the evolution of the polymer micro- or nano-structures for this patterning process.

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Flow behavior at the embossing stage of nanoimprint lithography

Cited by 62 publications

References 9 publications

Limitations of Simple Flow Models for the Simulation of Nanoimprint

Limitations of Simple Flow Models for the Simulation of Nanoimprint

Nanoimprint Lithography

Numerical studies of electrically induced pattern formation by coupling liquid dielectrophoresis and two‐phase flow

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