The invention relates to fluid paths in etchable materials. Fluid paths are formed by forming a cavity through a substrate material with a first dry removal process to produce a first surface of the cavity. The first surface of the cavity is associated with a first roughness. The first surface of the cavity is etched with a second wet removal process to reduce the first roughness and produce a second roughness associated with the first surface of the cavity. A coating is applied to the first surface of the cavity to produce a second surface to improve wettability of the first or second surface of the cavity, reduce in size or number gas nucleation sites in the first or second surface of the cavity, reduce the amount of debris associated with the first roughness carried by the fluid flow, and/or improve hydrophilicity of the first or second surface.
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