Methods of forming memory device storage capacitors using protruding contact plugs

Abstract

Methods of forming memory device storage capacitors include the steps of forming a first electrically insulating layer on a semiconductor substrate containing active and inactive regions therein and then forming a first contact hole in the first electrically insulating layer to expose the active region. A step is also performed to form a first electrically conductive contact plug in the first contact hole and in ohmic contact with the active region. A second electrically insulating layer is then formed on the first electrically insulating layer. Next, a second contact hole is formed in the second electrically insulating layer, to expose the first electrically conductive contact plug. A second electrically conductive contact plug is then formed in the second contact hole and in ohmic contact with the first electrically conductive contact plug. A step is then performed to etch back the second electrically insulating layer to expose sidewalls of the second electrically conductive contact plug. Then, an electrically conductive material is conformally deposited on the protruding second electrically conductive contact plug. Because of the conformal deposition, the thickness of the deposited electrically conductive material is increased in a region closely surrounding a perimeter of the protruding contact plug. This increase in thickness provides an over-etch margin which lessens the likelihood that a reduced-area contact will be formed between the lower capacitor electrode and the second electrically conductive contact plug when the lower capacitor electrode is patterned.

Dependencies are inferred from the claim text.