Design of experiments in electrochemical microfabrication

Electrochemical material etching techniques have attracted a significant amount of attention in the “wet” metal etching arena, as the process typically involves neutral salt electrolytes and is relatively safe to operate. There are also economical and environmental advantages associated with these techniques compared with competing etching methods.A new concept of electrochemical microfabrication on substrates has been developed. In the technique the workpiece, which is the anode in the electrochemical reactor, is placed closely to a tool, which is the cathode containing the micro-pattern. Selective pattern transfer results in a higher etching rate on the areas opposing “exposed” regions of the cathode, and lower etching rates in the areas directly opposite to the areas, on the cathode, covered by an insulator.In this investigation the electrochemical micro-patterning process has been evaluated and characterised in a vertical flow system described previously in literature. The experiments were carried out using copper disk anodes and patterned cathodes in a 0.1 M copper sulphate electrolyte. A 24 factorial experimental design procedure was adopted to determine the influence of process parameters on the electrochemical microfabrication process in terms of variability in pattern transfer over the electrode's surface area.