Membrane mask for short wavelength radiaton exposure process

摘要

In an electron or particle beam structuring mask, consisting of a semiconductor wafer (2) with an apertured layer (1) on one surface and with a recess (3) extending from the other surface to the layer-bearing surface, the layer (1) is a preferably 0.1-2.0 mu m thick silicon nitride layer. Also claimed is a similar electron beam structuring mask having, between the apertured layer (31) and the wafer (32), a continuous layer (30) consisting of a combination of silicon dioxide (34), silicon nitride (35) and silicon dioxide (36) layers of relative thicknesses such that the combination is under a slight tensile stress preferably of about 108 dynes/cm2. Also claimed is a mask production process involving plasma etching of the apertures in the mask-defining layer (1, 31) at -90 to -140 degrees C using a helicon source for plasma generation and an etching gas mixture of SF6 and O2 in a ratio resulting in perpendicular aperture walls.