Abstract: The gas feed system disclosed herein is useful in a reactive ion etching system in which a gas plasma is energized by an electrode plate through which the gas is introduced. Propagation of the plasma discharge down the gas feed path is blocked by a feed system in which the space between a pair of porous metal plugs is filled with a porous insulating material having a pore size too small to support discharge, i.e. corresponding to the mean free electron path in the gas.

Abstract: A novel method for preparing a stencil master, a novel stencil and a method for printing therefrom are provided. The method for preparing the stencil comprises coating a suitable screen with a curable silicone containing a curing catalyst, depositing a particulate image pattern on said coated screen with a material which selectively inactivates said curing catalyst below said image pattern, curing the resultant nonimaged silicone to an elastomeric ink releasable condition and removing the particles from said particulate image pattern and the uncured silicone below said pattern to provide perforations in imagewise configuration. The method for printing comprises the additional steps of contacting the resultant screen with an image receiving member and passing ink through said perforations to thereby form an inked image on said receiving member.