Patent ID: 8377813

Claim:
A method for forming a buried split word line structure, comprising: providing a substrate having a trench therein; forming a conductive material conformal to the trench; depositing a first insulating layer within the trench adjacent the conductive material; etching the first insulating layer to a first etched depth; etching the conductive material to a second etched depth in accordance with the first etched depth to thereby form a U-shaped gate conductor; depositing a second insulating layer above the U-shaped gate conductor and conformal to the trench; and etching away portions of a third insulating layer, the U-shaped gate conductor and the substrate to form a recess in substrate so that the U-shaped gate conductor is split into two halves; wherein the third layer is formed above the U-shaped gate conductor and the second etched depth is greater than the first etched depth.