Large-area microwave plasma etching of polyimide

The authors have investigated O 2 /CF 4 plasma etching of DuPont Kapton 'H' polyimide film using a new large-area microwave plasma apparatus. Uniform etching of a 700 cm 2 sample area is achieved by combined rotational and translational motion of the substrate holder with respect to the microwave applicator. They have investigated the effect of various operating parameters, namely, pressure, etchant gas composition and flow rate, discharge power, and substrate temperature. A sharp maximum in etch rate is observed at 0.2 Torr (27 Pa) and 12% CF 4 in O 2 ; the thermal activation energy is found to be E a =0.21+or-0.02 eV. These data agree well with recent findings by other workers.