Semiconductor device and method of manufacturing the same

A method of manufacturing a semiconductor device comprising a semiconductor body (1) which is provided at a surface (2) with a non-volatile memory cell, by which method a gate structure (8) comprising a control gate (7 is formed at the surface (2) of the semiconductor body (1), the gate structure (8) being electrically insulated from the semiconductor body (1) by a gate dielectric (11,25), which gate dielectric (11,25) is provided with a charge-storage region wherein data in the form of electric charge is stored, after which a conductive layer (20) is applied in a thickness such that the upper surface (24) of the conductive layer (20) next to the gate structure (8) is located at substantially the same height as, or higher than, the top surface portion (23) of the gate structure (8), which conductive layer (20) is removed over a part of its thickness by means of a planarizing treatment until the gate structure (8) is exposed, after which the conductive layer (20) is patterned, while using a mask (21) to provide an access gate (14), which mask (21) stretches out from the gate structure (8) over a region of the conductive layer (20) adjoining the gate structure (8).