After exposure to UV and temperature processes, the glass crystallizes, transformed into a photosensitive glass ceramic (ceramization). Without the efforts of photolithography, the crystallized areas can be etched away with hydrofluoric acid. The SCHOTT product features a high 30:1 glass to crystallized area etch selectivity ratio for easy process.
When lithography is applied to regular glass, etch process develops isotropic and is hard to achieve a high aspect ratio. On the contrary, photosensitive glass only needs to selectively etch away the crystallized area with literally no limitation on aspect ratio, resulting in 20～30μm fine structures.