A mask (38), which is particularly useful in parallel-printing ion beam lithography because of its dimensional stability, is disclosed. The mask (38) represents a relatively rigid screen (22) constructed from a relatively rigid material, such as monocrystalline silicon, with meshes (28) formed through the screen (22) over the entire area of the screen (22). The preferred embodiment applies a less rigid filler material (34) into the meshes (28) over the entire area of the screen (22), then removes the filler material (34) from transmissive areas (42) of the mask (38).