Stability of Laser-Patterned Electrode Compositions

Abstract

Electrodes can be created with maskless metallization of Cu tracks ablated with laser direct structuring on the surface of a Cu–liquid-crystal polymer composite. The composition of these electrodes may not be stable in a corrosive environment, such as an electrolyte, which is needed to use these structures as conductometric sensors. We have evaluated five different electrode compositions in a low corrosive environment and found electroless palladium–immersion gold to be the most stable. The other electrode compositions have pinholes in the metal layers enabling metal migration and local galvanic corrosion. We also investigate the effect of CO2 snow jet cleaning on the electrodes and its relationship with the electrode composition stability. The CO2 snow jet cleaning leads to smoother electrode surfaces. A smooth electrode surface will have fewer imperfections and therefore less metal migration and galvanic corrosion.