Use of novel chemical dipping method for the stability evaluation of an ultrathin TaNx barrier in Cu interconnects

Abstract

When a dip test in buffered oxide etching chemicals is combined with narrow contact pattern, the test can be used as a simple barrier evaluation method, especially for predicting of IPVD (Ionized Physical Vapor Deposition) extendibility. In spite of the excellent coverage of IPVD TaNx films the structural defect at the corner of the pattern could be the root cause of device degradation. The use of extremely thin IPVD TaNx film of around 20 A was limited by the contact of less than 0.2 μm and an AR (Aspect Ratio) value greater than 4:1.