Patent ID: 8497173

Claim:
A method for manufacturing a semiconductor device comprising: forming a first recess over a semiconductor substrate; forming a first insulation film over the first recess and the semiconductor substrate; forming a plurality of second recesses under the first recess by etching the first insulation film and the semiconductor substrate; forming a second insulation film over the second recesses and the first insulation film; forming gate patterns over the second insulation film, wherein the gate patterns each fill in the second recesses and extend upwards while having a substantially uniform width; and forming a second insulation film pattern and a first insulation film pattern located at the surface of the substrate at a first edge and at a second edge of each of the gate patterns by etching the second and the first insulation films until the semiconductor substrate is exposed, wherein a sum of a thickness of the second and a thickness of the first insulation film patterns is different from each other at the first edge and at the second edge.