Direct writing of thin and thick metal films via micro glow plasma scanning

This paper presents the first micro-scale process for local deposition and direct writing of metal films through sputtering of a micromachined target electrode. The deposition process is achieved via a highly confined micro glow plasma generated between the electrode's tip and the substrate at atmospheric pressure. Using cylindrical copper electrodes with diameters down to 40 μm, a micro glow is stably established to show local deposition of the material on doped silicon. The controlled manipulation of microplasma enables direct writing of the target material, for thicknesses ranging from the 100-nm order to over 5 μm variable with the discharge and scanning conditions. The feasibility of non-planar patterning is also demonstrated. The process is promising for rapid and low-cost production of thin-film patterns and possibly thick three-dimensional microstructures.