Increasing programming silicide process window by forming native oxide film on amourphous Si after metal etching

摘要

A method of forming a misalignment immune antifuse is presented comprised of the following steps. A partially processed semiconductor wafer is provided, containing at least one device electrically connected to a conducting region extending almost to the wafer surface, where the conducting region is surrounded by a dielectric layer which reaches the wafer surface. A blanket layer of amorphous silicon is deposited followed by deposition of a thin blanket layer of TiN and these layers are etched down to the dielectric surface except for that above the conducting region and some of the surrounding dielectric. A thin native oxide is formed over the exposed surface of the amorphous silicon. This is followed by deposition of a thicker TIN layer and of a metallization layer, which are patterned and etched so that contact is made to the lower layers. The oxidation step is repeated so as to oxidize any amorphous silicon surface that may have been inadvertently exposed in the last etching step.