METHOD AND APPARATUS FOR THE ETCHING OF PHOTOMASK SUBSTRATES USING PULSED PLASMA

摘要

Disclosed is a method and apparatus for the etching of a thin film upon a photomask 24 . The etching is carried out in a reactor 20 via an inductively coupled pulsed plasma. Pulsing of the plasma is achieved by regulating the time period or duty cycle in which the plasma is generated. It has been found that by decreasing the duty cycle, high etch selectively can be achieved and feature sizes can be faithfully maintained.