Chemical deposition of metals for the formation of microstructures: An alternative method to galvanoforming?

Injection moulding with LIGA-made moulding devices allows the inexpensive production of plastic microstructures. The production of metallic microstructures by replication of plastic predecessors is under development. The potential of electrochemical and chemical metal deposition is discussed and compared with respect to process parameters that determine the filling behaviour. Nickel is used as a model system. For the electrochemical deposition, two regimes were found. At low aspect ratios, transport processes were dominant, whereas at high aspect ratios the penetration of the electric field into the slit was insufficient to yield a satisfactory deposition thickness at its bottom. In contrast, chemical deposition was not directly limited by the aspect ratio, but by the formation of gas blankets that hinder the deposition process. Ultrasonic sound was found to effectively remove gas bubbles.