The disclosed technology is related to a method that includes the formation of contact vias for contacting gate electrodes and source (S) or drain (D) electrodes of nano-sized semiconductor transistors formed on a semiconductor wafer. The electrodes are mutually parallel and provided with dielectric gate and S/D plugs on top of the electrodes, and the mutually parallel electrode/plug assemblies are separated by dielectric spacers. The formation of the vias takes place by two separate self-aligned etch processes, the Vint-A etch for forming one or more vias towards one or more S/D electrodes and the Vint-G etch for forming one or more vias towards one or more gate electrodes. According to the disclosed technology, a conformal layer is deposited on the wafer after the first self-aligned etch process, wherein the conformal layer is resistant to the second self-aligned etch process. The conformal layer thereby protects the first contact via during the second self-aligned etch.