Method of forming openings in a semiconductor device and semiconductor device

A method of forming openings (26) to a layer (4, 6, 14) of a semiconductor device comprises forming a dielectric layer (20) over the layer of the semiconductor device, and forming a mask (23) over the dielectric layer. The mask comprises a plurality of mask openings (24, 25) arranged in a regular pattern extending over the dielectric layer and the plurality of mask openings include a plurality of first mask openings (24) and a plurality of second mask openings (25), each of the plurality of first mask openings (24) being greater in size than each of the plurality of second mask openings (25). The method further comprises reducing the size of the plurality of second mask openings (25) such that each of the second mask openings (25) is substantially closed and removing portions of the dielectric layer (20) through the plurality of first mask openings (24) to provide openings (26) extending through the dielectric layer (20) to the layer (4, 6, 14).