Dry andwet etching techniques based onsiliconand other semiconductor technologies are well known. For many metals, etching is a relatively cheap and well-established technique to obtain freeform structures with dimensions in the submillimeter range. This technique iswelldescribedinthe literature[1–5,7].Aphotosensitivepolymermask material is applied on themetal to be etched. Themask is exposed to light via a primary maskwithstructural technologiesare applicable, andtheirdetails canbefoundintheliteratureonsemiconductorprocessingor inRefs[1–3].Thepolymer is that thenon-exposedparts are polymerizedinsuchaway that they cannot be diluted by a solvent that is used to remove the rest of the polymer covering the parts to be , amask is formed, and themetal is etched through theopeningsof etchingmask,other techniques suchasdirect mask writing with a laser are also possible.
