M. Kendig et al., MICROSCOPIC AND ELECTROCHEMICAL MONITORING OF THE CATHODIC DEGRADATION OF POLYIMIDE-COATED A1-METALLIZATION, Electrochimica acta, 38(14), 1993, pp. 1877-1881
Cathodic degradation of polyimide-coated aluminum metallization on Si
substrates has been investigated using electrochemical impedance spect
roscopy simultaneously with either light optical or acoustic microscop
y. Water uptake by the polyimide can be monitored using the coating ca
pacitance and correlates with a change in the polyimide acoustic respo
nse. The capacitance of a defect increases with the area degraded by c
athodic corrosion due to external cathodic bias.