Method of protecting against electrochemical effects during metal etching

Claim 1

IN THE METHOD OF ETCHING PORTIONS OF A METAL LAYER FORMED ONLY ON THE FRONT SURFACE OF A SLICE OF SEMICONDUCTOR MATERIAL CONTAINING CURRENT CONDUCTING PATHS FROM ITS BACK SURFACE TO ITS FRONT SURFACE, SAID METAL LAYER BEING SEPARATED IN PLACES FROM SAID SEMICONDUCTOR MATERIAL BY INSULATION AND THE ETCHANT USED BEING SELECTED TO SUBSTANTIALLY ETCH ONLY THE METAL LAYER, COMPRISING THE STEP OF MASKING SAID METAL LAYER AND ETCHING AWAY THE UNMASKED PORTONS OF SAID METAL LAYER, THE IMPROVEMENT COMPRISING THE STEPS OF: PLACING AN INSULATION RESISTANT TO THE ETCHING SOLUTION ON THE EDGES AND BACK SIDE OF SAID SLICE PRIOR TO SUBMERGING SAID SLICE IN AN ETCHING SOLUTION, SUBMERGING THE INSULATION COATED SLICE IN THE ETCHANT SOLUTION FOR REMOVING THE UNMASKED PORTIONS OF THE METAL LAYER, AND REMOVING SAID SLICE FROM THE ETHANG SOLUTION, SAID INSULATION PREVENTING THE FORMATION OF ANY ELECTROEHCMICAL EFFECTS BETWEEN THE MATRIAL TO BE ETCHED AND THE SUBSTRATE.