Fabrication of optical wave-guides in silica-on-silicon by nickel electroplating and conventional reactive ion etching

A novel process for the fabrication of deep optical waveguides in silica-on-silicon for optical processing applications has been developed. It makes use of nickel electroplating to conform precisely e-beam written smooth curved structures and to use the deposited nickel to etch deeply (up to 8 μm) into silica layers. It is demonstrated that nickel plating offers substantial advantages in terms of resistance and resist mold fidelity than more conventional etch masks such as patterned metal layers. The etching process, that is based on conventional fluorine reactive ion etching, has been optimized by making use of a design of experiment technique, details of process optimization and comparative analysis of different etching mask performances are also given.