Patent ID: 8202784

Claim:
A method for manufacturing a semiconductor device, comprising the steps of: defining a first trench and a second trench in a semiconductor substrate such that the second trench is wider than the first trench; forming a first insulation layer over the semiconductor substrate and over the first and second trenches so that an entrance of the first trench is clogged by the first insulation layer and so that the first insulation layer is deposited within the second trench; cleaning the first insulation layer to open up the clogged entrance of the first trench; and forming a second insulation layer to substantially fill in the second trench, in which the first insulation layer is already partially filled and forming the second insulation layer to substantially fill in the first trench, wherein the first trench is defined between storage node contact zones adjoining each other, and the second trench is defined between bit line contact zones facing each other.