Patent ID: 7195973

Claim:
A method for fabricating a trench capacitor with an insulation collar in a substrate, which is electrically connected to the substrate on one side via a buried contact, comprising: providing a trench in the substrate using a hard mask with a corresponding mask opening; providing a capacitor dielectric in the lower and central trench region, the insulation collar in the central and upper trench region and an electrically conductive filling at least as far as a top side of the insulation collar, the top side of the insulation collar being spaced apart from the top side of the substrate; sinking the electrically conductive filling to below the top side of the insulation collar; forming an insulation region on one side with respect to the substrate above the insulation collar; forming a connection region on a different side with respect to the substrate above the insulation collar; and forming the buried contact by depositing and etching back a conductive amorphous metal filling.