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Determination of adhesive forces and sticking temperature of coated glasses for the hot-embossing-process

Bestimmung von Haftkräften und Klebetemperatur von beschichteten Gläsern für den Heißprägeprozeß
 
: Worsch, C.; Edelmann, J.; Rüssel, C.; Schubert, A.

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Preprint urn:nbn:de:0011-n-1745933 (748 KByte PDF)
MD5 Fingerprint: 6dee76713dcffdf45fa471d76d8ebe85
The original publication is available at springerlink.com
Erstellt am: 2.8.2011


Microsystem Technologies 17 (2011), Nr.8, S.1401-1406
ISSN: 0946-7076
Englisch
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWU ()
glass; glass forming; hot embossing; glass pressing; precision glass moulding; thin films; glass coating; microfluidics; micro optics; MEMS Glas; Glasformgebung; Heißprägen; Blankpressen; Präzisionsblankpressen; Beschichtung; Mikrofluidik; Mikrooptik; Mikrosystemtechnik

Abstract
In contrast to previous studies a new coating strategy was developed to decouple the viscosity in the glass volume from the sticking behaviour at the glass surface. Not the mould, but the glassy substrate was coated with a thin, adhesive and ductile layer. For that purpose, soda-lime silica and borosilicate glasses were coated with gold, chromium, carbon, silica or titanium oxide. The isothermal hot embossing was carried out under air or, however, under argon atmosphere with a pressure of 500 Pa. Under vacuum inert gas atmosphere, all examined coatings shift the sticking temperatures by around 80 K to temperatures near the Littleton-temperature of the glass, which is even higher than the temperature process range of micro structuring. The adhesive forces are <10% in comparison to those observed at uncoated glass substrates. Under air, the increase in the sticking temperature is not as pronounced. The coatings on the glass enable to apply hot embossing at higher temperatures and hence at smaller viscosities. Hence high shear rates and a reduction of embossing forces are enabled.

: http://publica.fraunhofer.de/dokumente/N-174593.html