Patent ID: 7273790
Filing Date: 2007-09-25
Classification: H01L

Abstract:
1. A method for fabricating a trench capacitor in a substrate, which comprises: providing a trench with trench walls in the substrate utilizing a hard mask with a corresponding mask opening, the trench having the lower, central, and upper trench regions; providing a capacitor dielectric in the lower and central trench regions; providing an insulation collar in the central and upper trench regions, the insulation collar having a topside; providing an electrically conductive filling at least as far as the topside of the insulation collar; subsequently depositing a nitride liner layer; subsequently completely filling the trench with a filling material; carrying out an STI trench fabrication process; removing the filling material and sinking the electrically conductive filling to below the topside of the insulation collar; subsequently forming spacers at the trench walls above the insulation collar; removing portions of the spacers disposed above the connection region; forming an insulation region on a first side with respect to the substrate above the insulation collar; masking at least one portion of the spacers disposed above the insulation region with a silicon liner; uncovering a connection region on a different side with respect to the substrate above the insulation collar; and forming a buried contact electrically connecting the filling of the trench to the substrate on one side of the trench by depositing and etching back a metallic filling.