Production method for a trench capacitor with an insulation collar

摘要

The present invention provides a method for fabricating a trench capacitor, in particular for use in a semiconductor memory cell (100), with an insulation collar (168'; 168''), having the following steps: provision of a substrate (101); formation of a trench (108) in the substrate (101); provision of a first layer (177) on the trench wall; provision of a second layer (178) on the first layer (177) on the trench wall; filling of the trench (108) with a first filling material (152); removal of the first filling material (152) from the upper region of the trench (108) in order to define a collar region; removal of the second layer (178) from the upper region of the trench (108); removal of the first filling material (152) from the lower region of the trench (108); removal of the first layer (177) from the upper region of the trench (108); local oxidation of the upper region of the trench (108) in order to produce the insulation collar (168'; 168''); removal of the first and second layers (177; 178) from the lower region of the trench; formation of a dielectric layer (164) in the lower region of the trench (108) and on the inner side of the insulation collar (168'; 168''); and filling of the trench (108) with a conductive second filling material (161).