A Consideration of Important Factor on Demolding Force for Various Molds

Kawata, Hiroaki; Ishihara, Jyunya; Tanabe, Toshiaki; Yasuda, Masaaki; Hirai, Yoshihiko

doi:10.2494/photopolymer.25.223

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…With such large features as those needed for micromolding, patterned coatings can be deformed due to the strong adhesion between the coating and the mold in the presence of interfacial microstructures; demolding may even fail, resulting in permanent contamination of the mold. It has been shown at the nanoscale that coatings with low surface energies will reduce demolding-related defects, , and investigations of the demolding force have shed light on this aspect of the nanoimprinting processes (where the whole mold is separated from a nanostructured coating in a normal separation direction). − …”

Section: Introductionmentioning

confidence: 99%

Modulus- and Surface-Energy-Tunable Thiol–ene for UV Micromolding of Coatings

Sakizadeh

Weiblen

et al. 2017

ACS Appl. Mater. Interfaces

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Micromolding of UV-curable materials is a patterning method to fabricate microstructured surfaces that is an additive manufacturing process fully compatible with roll-to-roll systems. The development of micromolding for mass production remains a challenge because of the multifaceted demands of UV curable materials and the risk of demolding-related defects, particularly when patterning high-aspect-ratio features. In this research, a robust micromolding approach is demonstrated that integrates thiol-ene polymerization and UV LED curing. The moduli of cured thiol-ene coatings were tuned over 2 orders of magnitude by simply adjusting the acrylate concentration of a coating formulation, the curing completed in all cases within 10 s of LED exposure. Densely packed 50-μm-wide gratings were faithfully replicated in coatings ranging from soft materials to stiff highly cross-linked networks. Further, surface energy was modified with a fluorinated polymer, achieving a surface energy reduction of more than a half at a loading of 1 wt %, and enabling tall (100 μm) defect-free patterns to be attained. The demolding strengths of microstructured coatings were compared using quantitative peel testing, showing its decrease with decreasing surface energy, coating modulus, and grating height. This micromolding process, combining tunability in thermomechanical and surface properties, makes thiol-ene microstructured coatings attractive candidates for roll-to-roll manufacture. As a demonstration of the utility of the process, superhydrophobic surfaces are prepared using the system modified by the fluorinated polymer.

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Section: Introductionmentioning

confidence: 99%

Modulus- and Surface-Energy-Tunable Thiol–ene for UV Micromolding of Coatings

Sakizadeh

Weiblen

et al. 2017

ACS Appl. Mater. Interfaces

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show abstract

“…The stress mechanism of the resist and template and the reasons for defects were analyzed [2][3][4]. To suppress the release load and eliminate defects, using novel mold with low surface energy materials [5], increased performance of the resist [6], structure modification or novel template release methods have been proposed [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Debonding Problem during Demolding Process of Nanoimprinting

Wang

Zhang

et al. 2017

J. Photopol. Sci. Technol.

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Template release process during nanoimprint lithography was investigated, and the detailed steps of this process were described in order to reduce defects caused by demolding process. The debonding problem was discussed by using optimization of model, numerical simulation and theoretical analysis. The rules and mechanism of debonding were obtained by analyzing the relations between the bonding strength and the vertical stresses of the cementing surface linking the residual layer and the substrate in terms of stress balance theory in fracture mechanics. The location and demolding process which is prone to debond were analyzed. It is concluded that the debonding phenomenon took place at the intermediate position during the second demolding stage, when the adhesion force between the resist and the mold was 0.8 times of other interfaces between the mold and the resist. The debonding phenomenon took place at the angular position during the fourth demolding stage, when the adhesion force between the resist and the mold was 1.2 times bigger than the other interfaces between the mold and the resist.

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A Consideration of Important Factor on Demolding Force for Various Molds P223-6

Kawata

Ishihara

Tanabe

et al. 2012

J. Photopol. Sci. Technol.

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The demolding forces for various molds are studied for thermal imprint process. Molds are fabricated by anisotropic KOH etching of (110) Si wafer and conventional plasma etching. Although the side wall roughness by the KOH etching is much smaller than that by the plasma etching, the demolding forces for the both molds are similar. The demolding forces for the molds with various cavity depths are measured, and it is found that the demolding force depends on the total side wall area. The demolding force for the mold with line and space pattern is about 50 times as large as that for the mold with no patterns. These results show that the demolding force from the side wall is dominant in the thermal imprint process.

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A Consideration of Important Factor on Demolding Force for Various Molds

Cited by 4 publications

References 8 publications

Modulus- and Surface-Energy-Tunable Thiol–ene for UV Micromolding of Coatings

Modulus- and Surface-Energy-Tunable Thiol–ene for UV Micromolding of Coatings

Analysis of Debonding Problem during Demolding Process of Nanoimprinting

A Consideration of Important Factor on Demolding Force for Various Molds P223-6

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