New Degradation Phenomena of Stress-Induced Voiding Inside via in Copper Interconnects

Abstract

Stress induced voiding inside vias has been investigated in detail using three different kinds of test patterns. Resistance increase which is caused by voiding inside via has been seen larger in "extrusion pattern" than in "wide pattern". The resistance shift depends upon the length of the narrow pattern within the "extrusion pattern". Our new finding is that resistance shift through 10Khour is dominated by the "body metal area". These phenomena can be explained with the effect of vacancy diffusion through the path of the copper and barrier metal side interface.