Abstract: A pellicle for isolating a photomask pattern from particulate contaminants. The pellicle includes a peripheral frame having at least one vent structure for the passage of a gaseous substance between the interior of the frame and the atmosphere outside of the frame. The vent structure is configured for removal of particulate contaminants from the gaseous substance before the gaseous substance flows into the interior of the frame. The vent structure includes at least one exterior passageway extending between two openings in the outer surface of the frame and at least one interior passageway extending inwardly from the exterior passageway to an opening in the inner surface of the frame.

Abstract: A process for forming a defect-free photomask consisting of an opaque layer overlying a substrate transparent to radiant energy and which comprises applying a coating material which absorbs radiant energy to the surface of a substrate, directing a beam of radiant energy through the substrate onto the coating material so as to fuse the coating material and the substrate at their interface thereby forming an opaque layer on said substrate, and removing from the surface the unfused coating material.