A lens layer of P- and B-doped SiO₂ was formed on the SiO₂ substrate by LSCVD® equipment to achieve a predetermined reflow temperature, which was dry-etched in a cylindrical form by ICP etching equipment, and then reflow (in the range of 900-1150°C) was performed to form the lens. The curvature of the lens can be controlled by etching conditions, film thickness, reflow temperature, etc.
Photo courtesy of National Institute of Advanced Industrial Science and Technology