Proceedings Article | 5 April 2007
Iraj Emami, Vladamir Ukraintsev, Bill Banke, Chas Archie, Bryan Rice, Benjamin Bunday, Mark Caldwell, Bhanwar Singh, Eric Solecky, Jennifer Morningstar, John Allgair, Dilip Patel, Alfredo Herrera, Pete Lipscomb, Jason Cain, Jeff Ritchison, Jerry Schlessinger
KEYWORDS: Metrology, Overlay metrology, Inspection, Semiconducting wafers, Process control, Yield improvement, Critical dimension metrology, Optical proximity correction, Etching, Lithography
The conventional premise that metrology is a "non-value-added necessary evil" is a misleading and dangerous assertion,
which must be viewed as obsolete thinking. Many metrology applications are key enablers to traditionally labeled
"value-added" processing steps in lithography and etch, such that they can be considered integral parts of the processes.
Various key trends in modern, state-of-the-art processing such as optical proximity correction (OPC), design for
manufacturability (DFM), and advanced process control (APC) are based, at their hearts, on the assumption of fine-tuned
metrology, in terms of uncertainty and accuracy. These trends are vehicles where metrology thus has large opportunities
to create value through the engineering of tight and targetable process distributions. Such distributions make possible
predictability in speed-sorts and in other parameters, which results in high-end product. Additionally, significant reliance
has also been placed on defect metrology to predict, improve, and reduce yield variability. The necessary quality
metrology is strongly influenced by not only the choice of equipment, but also the quality application of these tools in a
production environment. The ultimate value added by metrology is a result of quality tools run by a quality metrology
team using quality practices.
This paper will explore the relationships among present and future trends and challenges in metrology, including
equipment, key applications, and metrology deployment in the manufacturing flow. Of key importance are metrology
personnel, with their expertise, practices, and metrics in achieving and maintaining the required level of metrology
performance, including where precision, matching, and accuracy fit into these considerations. The value of metrology
will be demonstrated to have shifted to "key enabler of large revenues," debunking the out-of-date premise that
metrology is "non-value-added." Examples used will be from critical dimension (CD) metrology, overlay, films, and
defect metrology.
