Online information source for semiconductor professionals

Kelly Barry & Sanjay Yedur, Timbre Technologies, Inc., Santa Clara, CA, USA#

ABSTRACT

Optical digital profilometry (ODP) has for years been implemented for the metrology of 2D (i.e., line-space) structures at various process levels, including lithography, etch, and CMP. ODP provides critical dimension, crosssectional profile, and film thickness information for both stand-alone and integrated metrology applications. ODP is now being implemented for metrology of 3D hole and island structures for both lithography and etch process development and monitoring. This article discusses the application of 3D ODP metrology to post-lithography structures, where measurements of critical parameters can be made immediately following the lithography process, in a method nondestructive to the wafer. The results show that ODP can be used successfully to monitor CD, film thickness, and profile variation. Tool-precision results indicate the stability of the measurement process, and correlation to CD-SEM is also provided as a reference metrology, demonstrating that ODP is a viable 3D-metrology solution.