Deep etching of glass wafers using sputtered molybdenum masks

This note presents a simple, low-cost technology to fabricate very deep isotropically etched features in glass wafers. A process based on fast etching glass combined with a stress-optimized molybdenum mask layer and a photoresist was found to be very suitable for such purposes. The obtained performance, up to 1.2 mm deep etching, rivals the best existing techniques while being more cost-competitive and using widely available equipment.