Detecting faults in gate insulated semiconductor component

摘要

A voltage is applied between the semi-conductor substrate (1) and the gate electrode (4) in a chemical wet etching system (7) during each step. The position of a fault (6) in the gate insulating film (3) is determined from the difference of insulating film surface, when an anode oxide film (11) is formed on the gate electrode and when the latter is etched away. Preferably, part of the gate insulating film is coated with an anti-etching film. Typically, an aqueous KOH solution of 0.25 N at a temperature of 60 degrees C may be used as the chemical etching solution for the electrochemical wet etching.