Specifications, methodologies and results of evaluation of optical critical dimension scatterometer tools at the 90nm CMOS technology node and beyond

The Advanced Metrology Advisory Group (AMAG) is a council composed of the chief CD-metrologists from the SEMATECH consortium's Member Companies and from the National Institute of Standards (NIST). The AMAG wrote, with OCD tool supplier involvement, the "Unified Advanced Optical Critical Dimension (OCD) Scatterometer Specification for Sub-90nm Technology (2004 Version)" [22] to be a living document which outlines the required performance of OCD tools for supplier compliance to the 2003 International Technology Roadmap for Semiconductors (ITRS) and which conveys Sematech member companies' collective needs to vendors. Using this specification, evaluation efforts of currently available tools are being performed. The 2004 AMAG Unified Specification for Seatterometry includes sections outlining the test methodologies, metrics, and wafer-target requirements for each parameter to be benchmarked, and, if applicable, prescribes a target specification compatible with the ITRS. The methodologies are valid for the demands of the 90nm technology node and beyond. Parameters to be considered include: center dot Precision, Repeatability and Reproducibility center dot Accuracy center dot System Matching center dot Noise and Spectral Sensitivity center dot Throughput center dot Interaction with sample center dot Measurement of material optical properties (n & k) center dot Pattern recognition/stage navigation accuracy center dot Specular Beam Width ("spot size") center dot Cost of ownership (COO) When possible, the metrics in this specification have been made compatible with similar specifications in the AMAG CD-SEM Unified Specification so that fair intercomparisons of different tools can be made. Previous CD-SEM studies under this same project have been published, with the initial version of the International SEMATECH CD-SEM Unified Specification in 1998, and multi-supplier CD-SEM benchmarks in 1999, 2001 and 2003.