Arrayed Waveguide Gratings (AWGs) in silica on silicon technology were fabricated and tested in our laboratory. The silica optical layers were all deposited in LPCVD furnaces, and waveguide core was etched using a photoresist mask in an inductively coupled plasma source with C@sub 4@F@sub 8@/O@sub 2@/He gas mixture. This article reports the dependence of important process parameters, included aspect ratio dependent etch rate (A.R.D.E.) effect, selectivity and waveguide side wall angle, on RF power, chamber pressure and gas flow rates. In particular the effects of He and O@sub 2@ addition on A.R.D.E. effect and waveguide side wall angle were investigated. Based on these results a reliable and high throughput process was set up to etch silica waveguides suitable for AWG fabrication, with etch rate higher than 300 nm/min, selectivity on photoresist higher than 5:1 and waveguide side wall angle higher than 88.5°. Measurements of first 16 Channel 200 GHz AWGs fabricated with this process are presented and discussed. To conclude preliminary results are reported about etching of high aspect ratio (>3:1) trenches with depths greater than 15 µm, to be used for stress releasing grooves in AWGs.