IMPROVEMENT OF OPTICAL CONTROL MONITOR TO RECTIFY TUNGSTEN PARTICLE PEEL-OFF ISSUE

Abstract

Optical Control Monitor (OCM) structures are features along the scribe lines of wafers, which are required for a variety of functions. The designs of some of these structures have resulted in a tungsten particle peel-off issue, which is detrimental to wafer yield. This project attempts to rectify this issue by removing or redesigning potentially problematic OCM structures. Besides discussing the temporary measures currently in place to contain these issues, the various changes to be made to the overlay and non-overlay structures are introduced and explained. Finally, experimental procedures to verify the effectiveness of the OCM changes and to determine the optimal overlay specifications are proposed.