Method for fabricating an insulation collar in a trench capacitor

摘要

A trench capacitor is formed with an insulation collar. After the formation of the trench, firstly an insulating layer is deposited, from which layer the insulation collar will be subsequently formed. Afterward, the trench is partly filled with a sacrificial filling material and a thin patterning layer is deposited thereon. Spacers are formed from that layer and cover the insulating layer in the upper region of the trench. Afterward, the sacrificial filling material and the insulating layer are completely removed in the lower region of the trench. As a result, the insulation collar is produced in the upper region of the trench.