MICROMACHINING OF TIN OXIDE FILM BY ELECTROCHEMICAL REDUCTION PROCESS

Tin oxide (SnO2) thin film was micromachined by the electrochemical re duction process in various electrolyte solutions. The electrode gap, c urrent density, and kind of electrolyte solutions for electrochemical reduction of tin oxide film were optimized. Very high resolution was a chieved in neutral or basic solutions, when the electrode gap was 0.1 mm and a large current density such as 5 A/cm(2) was applied for very short time, 1 s. High current density and very short reaction time avo ided the deposition of reduced species of tin oxide on the machined ar ea, resulting in the high resolution. Moreover, photolithographical pa ttern etching of five parallel straight lines with the widths 0.02-0.1 mm was performed and very high resolution was obtained when the subst rate was patterned and the Pt plate was used as counter electrode.