The invention defines a method for fabricating a semiconductor insulation layer: A semiconductor substrate is first provided; an insulation layer is applied by way of region-by-region or whole-area application to the semiconductor substrate; impurity ions are selectively implanted into at least one predetermined zone of the insulation layer; then the insulation layer is selectively etched, and the insulation layer is thereby patterned in accordance with the zone or zones of the selectively implanted impurity ions.