Characterization of the effect of TiN oxidation on via resistance

A failure mechanism due to presence of an oxygen interface at the via bottom was identified. Our in depth experimental analysis indicate that this interface layer is formed due to oxidation of TiN layer during oxygen plasma exposure and the marginality of the RF sputter etch step that is performed prior to via barrier deposition. TEM and EDX analysis of high resistance vias confirmed the presence of an oxidation TiN layer at the bottom of the via.