Crystallisation of Foturan® glass–ceramics

hotostructurable glass–ceramics are suitable for 3-dimensional microfabrication and, in some instances, can be used as an alternative material o silicon in the microfabrication of micro-electro-mechanical-system (MEMS) devices. Foturan® is a photosensitive lithium–aluminium–silicate lass that can be structured by an exposure to UV light, followed by a thermal treatment and an etching step. In this work, the crystallisation inetics and microstructure evolution of unexposed and UV-exposed Foturan® are investigated by means of differential scanning calorimetry, -ray diffraction and scanning electron microscopy. The glass transition temperature Tg, the apparent activation energy of crystallisation Ea and he colour of UV-exposed Foturan® are discussed. It is shown that nucleation and crystallisation of UV-exposed Foturan® can be steered either as function of temperature (non-isothermal) or as a function of time (isothermal). This is essential for the photostructuring and etching of Foturan® egarding the achievable feature sizes of 25 m for MEMS applications. 2011 Elsevier Ltd. All rights reserved.