Maskless pattern transfer into photostructured glasses by deep plasma etching

Pattern transfer by wet chemical and plasma etching requires etching masks that are stable against stresses emanating from the etching process and thus must have high selectivity. In the field of glass etching, hard masks are frequently used frequently, but they are relatively complex and expensive to manufacture. One of the aims is to avoid additional mask layers. This is strategy already used in plasma structuring but mainly for the fabrication of stochastically distributed micro- and nanostructures (e.g. black-Si). In this work, we present a method for a defined and parallel generation of microstructures without the need of additional etching masks. For this, we exploit two material phases that exist in photostructured glasses, which exhibit different etch rates in an etching plasma. It can be observed that the etch selectivity is reversed compared to wet chemical patterning protocols. Protruding structures made of glass ceramics with special material properties surrounded by the glassy phase are thus possible. This technology enables therefore new avenues in the field of defined, mask-free and anisotropic structuring.