Fabrication of deep square wave structures with micron dimensions by reactive sputter etching

Square wave gratings with periodicities as small as 1.4 μm have been etched into fused quartz by reactive sputter etching in CF4 and CHF3. Grooves with a perfectly rectangular cross section have been etched with a depth of up to 3 μm. The etching is probably due to highly reactive species produced directly on the substrate surface by an ion-induced dissociation process.