Extraction of Sheet Resistance and Linewidth from All-Copper ECD Test Structures Fabricated from Silicon Preforms

Test structures have been fabricated to allow electrical critical dimensions (ECD) to be extracted from copper features with dimensions comparable to those replicated in IC interconnect systems. The implementation of these structures is such that no conductive barrier metal has been used. The advantage of this approach is that the electrical measurements provide a non-destructive and efficient method for determining CD values and for enabling fundamental studies of electron transport in narrow copper features unaffected by the complications of barrier metal films. This paper reports on the results of various tests which have been conducted to evaluate the current design.