Patent ID: 7553737
Filing Date: 2009-06-30
Classification: H01L

Abstract:
1. A method for fabricating a recessed gate trench, comprising: forming a pad layer on a semiconductor substrate; forming a plurality of trench capacitors in the semiconductor substrate, wherein each trench capacitor is capped with a trench top layer; etching back the pad layer; forming a cap material layer on the semiconductor substrate; removing the cap material layer until the trench top layer is exposed to form the cap layer on the top surface of the pad layer; removing the trench top layer to expose a sidewall of the pad layer; laterally removing a portion of the exposed sidewall of the pad layer to define a residual pad layer; completely removing the cap layer; forming an oxide layer cover the semiconductor substrate; removing a portion of the oxide layer to expose the residual pad layer; removing the residual pad layer to form an opening in the oxide layer; and etching the recessed gate trench into the semiconductor substrate via the opening.