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The profile and etch depth of silica waveguide channel are inspected and measured with microscope and surface profiler respectively. Hexafluoroethane (C2F6) and tetrafluoromethane (CF4) plasma etching conditions were investigated for planar lightwave circuit (PLC) requirement. From the microscope images, suspected insufficient height of waveguide channel and chromium mask etch-off problem occurred after ICP etching by using CF4etch gas. By changing the fluorocarbon etch gas from CF4 to C2F6, chromium mask remained after etching process and found that there are some improvement of waveguide channel profile and selective etch for the etch results. The aim of 8 micron waveguide channel height is achieved by using C2F6 gas in ICP etching. This is agreed with process knowledge that fluorocarbon etch gas C2F6 is better than CF4 and suit the need for planar lightwave circuit silica etching process.