Photosensitive gas phase etching of semiconductors by selective radiation

Claim 1

IN THE FABRICATION OF A SEMICONDUCTOR DEVICE FROM A SEMICONDUCTOR WAFER OF ONE CONDUCTIVITY TYPE, THE STEPS OF FORMING A SILICON DIOXIDE LAYER ON A SURFACE OF SAID WAFER, SAID SILICON DIOXIDE BEING OF A DIFFUSION-RESISTANT THICKNESS, ENCLOSING THE THUS COATED WAFER IN AN AMBIENT IF5 GAS, DIRECTING AT SAID WAFER RADIATION IN ACCORDANCE WITH A PATTERN FOR A TIME AND AT A WAVELENGTH TO PENETRATE THE IRRADIATED PORTION OF SAID SILICON DIOXIDE LAYER AND EXPOSE SELECTIVELY SAID SURFACE, REMOVING SAID AMBIENT IF5 GAS AND SUBJECTING SAID SURFACE TO A VAPOR OF AN IMPURITY OF THE OPPOSITE CONDUCTIVITY TYPE FOR CONVERTING SELECTIVELY AT LEAST ONE SURFACE PORTION OF SAID WAFER TO THE OPPOSITE CONDUCTIVITY TYPE.