FOTURAN

FOTURAN is a photosensitive glass which enables it to be structured for a variety of purposes. This material combines the unique glass properties (transparency, hardness, chemical and thermal resistance, etc.) and the opportunity to achieve very fine structures with tight tolerances and high aspect ratio (hole depth/hole width). Smallest structures of 25 µm are possible with a roughness of 1 µm.

1. UV-Exposure
In the exposure step, FOTURAN glass is exposed to ultraviolet light at a wavelength between 290 - 330 nm. It is possible to illuminate material thicknesses of up to 2 mm. An energy density of approximately 20 Joule/cm² is sufficient to structurize a 1 mm thick FOTURAN plate.

2. Heat treatment
With the UV exposure step silver atoms are formed in the illuminated areas. During the heat treatment between 500^o and 600^oC the glass crystallizes around these silver atoms.

3. Etching
The crystalline regions, when etched with a 10% solution of hydrofluoric acid at room temperature, have an etching rate up to 20 times higher than that of the vitreous regions. If wet chemical etching is supported by ultrasonic etching or by spray-etching, the resulting structures display a large aspect ratio. Etching

1. UV-Exposure In the exposure step, FOTURAN glass is exposed to ultraviolet light at a wavelength between 290 - 330 nm. It is possible to illuminate material thicknesses of up to 2 mm. An energy density of approximately 20 Joule/cm² is sufficient to structurize a 1 mm thick FOTURAN plate.
2. Heat treatment With the UV exposure step silver atoms are formed in the illuminated areas. During the heat treatment between 500^o and 600^oC the glass crystallizes around these silver atoms.
3. Etching The crystalline regions, when etched with a 10% solution of hydrofluoric acid at room temperature, have an etching rate up to 20 times higher than that of the vitreous regions. If wet chemical etching is supported by ultrasonic etching or by spray-etching, the resulting structures display a large aspect ratio.