Foturan Photosensitive Glass

Foturan is a photostructurable glass ceramic (PSGC) manufactured by Schott Glass Corp and distributed by Invenios. Foturan is used as a MEMS and MOEMS substrate. Microfabrication in Foturan is achieved through patterning by a pulsed UV laser, a follow-up heat treatment step, and chemical etching. In Foturan, the exposed areas experience a selective phase change in which the native amorphous glass phase converts to a crystalline lithium silicate phase. The degree and type of crystallization are both responsive functions of the irradiation and thermal processing procedures. Under high exposure, the crystallized areas etch up to 30 times faster than the unexposed material in HF, with the etch rate varying with irradiation dose. Because Foturan is transparent at visible through IR wavelengths, direct-write XYZ exposure with a pulsed laser can detail complex 3-D structures within the Foturan material. Devices made from Foturan may be glass, a glass-ceramic composite, or ceramic, with the final material composition depending on the irradiation and thermal processing procedures. Excellent aspect ratios (>30:1) have already been demonstrated in Foturan.

At Invenios we make 3-D MEMS structures by implementing cost-effective manufacturing solutions that produce consistent results with a resolution measured in microns.

Invenios Foturan Resource Guide: Selected Articles about Photostructurable Glass-Ceramics

2004		Direct ultrafast laser writing of buried waveguides in Foturan glass	Stephen Ho and Peter R. Herman, Ya Cheng, Koji Sugioka, and Katsumi Midorikawa
2002		3D microstructuring inside Foturan glass by femtosecond laser	Ya Cheng, Koji Sugioka, Masashi Masuda, Koichi Toyoda,Masako Kawachi, Kazuhiko Shihoyama, and Katsumi Midorikawa
2005		Holography in commercially available photoetchable glasses	Michael Kösters, Hung-Te Hsieh, Demetri Psaltis, and Karsten Buse
2006		Integrating 3D photonics and microfluidics using ultrashort laser pulses	Ya Cheng, Koji Sugioka, Katsumi Midorikawa, and Zhizhan Xu
2007		GEM-type Detectors Using LIGA and Etchable Glass Technologies	S.K. Ahn, J.G. Kim, V. Perez-Mendez, S. Chang, K.H. Jackson, J.A. Kadyk, W.A. Wenzel and G. Cho
2005		Production and Characteristics of Microreactors made of glass	Thomas R. Dietrich, Andreas Freitag, Rolf Scholz
2005		Freestanding optical fibers fabricated in a glass chip using femtosecond laser micromachining for lab-on-a-chip application	Ya Cheng, Koji Sugioka, and Katsumi Midorikawa
2004		Micropatterning of photosensitive glass	University of Surrey | Guildford
2003		Three-dimensional micro-optical components embeded in photosensitive glass by femtosecond laser	Ya Cheng, Koji Sugioka, Masashi Masuda, Koichi Toyoda, Masako Kawachi, Kazuhiko Shihoyama, and Katsumi Midorikawa

Notes

Foturan is a photo-sensitive (UV-sensitive) glass distributed by Invenios.

• It is a lithium-potassium glass dotted with a small amount of silver and cerium oxides, produced by Schott Glass Corp.
• If Foturan glass is exposed through a mask to ultraviolet light at a wavelength between 290 & 330 nm and then warmed up to 600°C, a crystallic structure is formed in the illuminated areas.
• Foturan glass is then etched in a solution of hydrofluoric acid. The etching is anisotropic, however, the crystallized parts have the etching rate up to 20 times higher than the vitreous regions, which is sufficient to achieve high aspect ratio (hole depth to hole width).
• Micro-structures of size down to 20 micrometers can be made with a roughness of 1 micrometer.
• Either structured or unstructured individual parts of Foturan may be connected without any intermediate layer by thermal diffusion bonding.
• The advantage of this process is apparent: whole device is made from glass, there are no boundary regions with different (chemical, mechanical, optical) properties.

Please consult our applications engineering staff to learn how we can save reduce component count and reduce microsystem assembly costs using this revolutionary micromachining process. Contact your for more information.