Micro/Nano-3D Structuring of Glassy Carbon by FIB Etchingfor Hot Embossing of Glass Materials

Abstract

Micro/nano imprinting or hot embossing is of interest in the industrial production of microdevices. In fluidic MEMS (micro electro mechanical systems) applications, polymer materials have been employed, because of their low cost in the fabrication of economical products. However glass is much more suitable for higher temperature applications or strong chemical environments. In optical MEMS as well, glass is a good candidate materials because of their better optical properties. Si or Ni molds, usually employed for polymer forming, can not be used for glass forming because of their poor heat resistance and the difficulty of removal arising from cohesion between the mold and the glass. Glassy carbon (GC) is thus a suitable material for high-temperature embossing. In this study, FIB (focused ion beam) machining was employed for micro/nano 3D-structuring of GC materials, the machining characteristics are summarized as follows. 1) Machining depth is proportional to machining time, 2) nanomachining of 0.3 m resolution is possible, 3) smooth surface with maximum roughness of Ra=30nm after is formed 20 m deep machining, 4) implanted Ga ions precipitate up on 350 annealing, but disappear after annealing in vacuum at elevated temperatures. Finally a Pyrex-glass embossed structure is successfully fabricated by hot embossing with a good fidelity of 10x10x7 m in size and with a 0.3 m line and space pattern and 0.4 m depth.