that it may be advantageous to modify the cd of the etch mask to a value other than that induced by the main etch process for example the deposition process can be used to adjust the mean to target mtt of the final etched features to a target value that is different from the initial etch mask cd the passivation film may be carbon containing e g polymer based or diamond like carbon dlc or inorganic in nature e g silicon containing sulfur containing etc in the case of a polymer film the polymer may be formed using a hydrocarbon precursor in a preferred embodiment the hydrocarbon precursor is of the form c x h y e g ch 4 c 2 h 6 c 2 h 2 etc in another embodiment the polymer precursor may be a halocarbon typically the processes gases in a photolithographic etch process are introduced into the plasma source to enable more efficient ionization in some cases it may be advantageous to introduce gases nearly coplanar with the substrate in one embodiment a portion of at least one process gas is introduced into the process chamber outside the plasma generation zone in a preferred embodiment at least.