Method of forming openings in a semiconductor device and semiconductor device

A method of forming openings to a layer of a semiconductor device comprises forming a dielectric layer over the layer of the semiconductor device, forming a main mask over the dielectric layer, the main mask comprising a plurality of main mask openings arranged in a regular pattern extending over the dielectric layer, using a selector mask to select some of the plurality of main mask openings and removing portions of the dielectric layer through the selected some of the plurality of main mask openings to provide openings extending through the dielectric layer to the layer.