FORMATION OF ELECTRODE FOR SEMICONDUCTOR ION SENSOR

PURPOSE:To improve the productivity of a semiconductor ion sensor by coating a photosensitive resin on an element substrate on which an ion sensitive film is coated, subjecting the resin to photoengraving and coating a metallic layer thereon, then removing the photosensitive resin thereby forming the electrodes. CONSTITUTION:An n source region 2 and drain region 3 are formed on the surface of a P silicon substrate 1 and electrode junctures are exposed, then the surface is coated with the ion sensitive film 4 to manufacture an element substrate 7. The photosensitive resin 8 of a positive type is provided over the entire surface, is selectively exposed by UV rays and is developed. The substrate is then put into a vacuum deposition device where the metallic layer consisting of chromium, gold, etc. is deposited by evaporation. The photosensitive resin is finally dissolved by acetone, etc. and the unnecessary metal is stripped so that the metallic layer of the electrode junctures remains. The semiconductor ion sensor is thus formed. The contamination of the ion sensitive film is thus prevented and the easy formation of the electrodes with good accuracy is made possible without deterioration of sensitivity characteristic.