| 摘要 |
The present invention provides a method for fabricating a trench capacitor having an insulation collar ( 10; 10 a , 10 b) in a substrate ( 1 ), which is electrically connected to the substrate ( 1 ) on one side via a buried contact ( 15 a , 15 b), in particular for a semiconductor memory cell having a planar select transistor which is provided in the substrate ( 1 ) and is connected via the buried contact ( 15 a , 15 b), comprising the steps of: providing a trench ( 5 ) in the substrate ( 1 ) using a hard mask ( 2, 3 ) with a corresponding mask opening; providing a capacitor dielectric ( 30 ) in the lower and middle regions of the trench, the insulation collar ( 10 ) in the middle and upper regions of the trench and an electrically conductive filling ( 20 ) at least up to the top side of the insulation collar ( 10 ); completely filling the trench ( 5 ) with a filling material ( 50; 50'; 50''; 20 ); carrying out an STI trench production process; removing the filling material ( 50; 50'; 50''; 20 ) and lowering the electrically conductive filling ( 20 ) to below the top side of the insulation collar ( 10 ); forming an insulation region (IS; IS 1 , IS 2 ) on one side with respect to the substrate ( 1 ) above the insulation collar ( 10 ); uncovering a connection region (KS; KS 1 , KS 2 ) on the other side with respect to the substrate ( 1 ) above the insulation collar ( 10 ); and forming the buried contact ( 15 a , 15 b) by depositing and etching back a C filling ( 70; 70'; 70''; 70''').
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