Defect study on Nanoglass ® E porous ultra-low k material ( k∼2.2) for ultra-large-scale integration applications

Abstract

Defect study plays an important role in successful integration of Cu and ultra-low k (ULK). In this work, defect detection and classification were done on the single damascene Cu-Nanoglass ® E porous ULK ( k∼2.2) films. The major yield killer defects were analyzed and the root causes were isolated. A novel composite barrier scheme with a thin dielectric flash layer (DFL) deposited prior to Ta deposition was proposed for the purpose of defect reduction and yield enhancement. Further defect analysis and electrical test results proved that the introduction of SiCN DFL effectively improved the interface adhesion between Ta barrier and nanoglass and reduced Cu loss/Cu residue defects. As a result, the metallization reliability was improved.