Study on XeF2 pulse etching using wagon wheel pattern

This paper reports the developed XeF₂ etching system and measured etching characteristics using a wagon wheel pattern. A pulse etching was used and an etching sequence was controlled by a computer. The etching rate was in proportion to the number of pulses and higher in the initial 15 seconds of etching than in the rest of the etching. The etching rates were 2.5 μm per pulse vertically and 2.0 μm per pulse laterally for pulse duration of 180 sec. The etching rate increased as the aperture width of the wagon wheel pattern increased. The measured ratio between the etch depth and the lateral undercut was 1.3. These etching characteristics were independent of crystal orientation