Patent ID: 7425486

Claim:
A method for forming a trench capacitor, comprising: forming a trench in a semiconductor substrate; depositing a first trench dielectric into the trench for partially filling the trench in the semiconductor substrate; forming an etch stop layer on the trench partially filled with the first trench dielectric and along inner surfaces of the trench; depositing a second trench dielectric on the etch stop layer to fill the trench; removing the second trench dielectric and the etch stop layer to expose the first trench dielectric on the trench; and forming a conductive layer on the first trench dielectric in the trench, such that the conductive layer, the first trench dielectric and the semiconductor substrate function as a trench capacitor, wherein the second trench dielectric remaining on the etch stop layer in the trench is etched down to the etch stop layer by an end-point-mode etching.