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Damage Formed on Silicon Surface by Helicon Wave Plasma Etching

The damage formed on a silicon surface by exposure to helicon wave oxygen plasma is studied. Oxygen plasma is formed by the typical conditions employed for photoresist patterning. The damage density formed on a silicon surface decreased from 1.9×1016 to 9.3×1015/cm2 with an increase of helicon wave power from 500 to 2000 W. This decrease is mainly due to the increase of plasma density and to a decrease of self-bias voltage with the power increase. It must be noted that this phenomenon is much different from the damage changes in magnetic enhanced reactive ion etching (MERIE). However, the damage density increases with a bias power increase. These results show that much lower damage etching can be achieved by helicon wave plasma etching if higher helicon wave powers and lower bias powers are supplied.