Applications of image diagnostics to metrology quality assurance and process control

Abstract

The purpose of this paper is to define standard methods for effective and efficient image-based dimensional metrology for microlithography applications in the manufacture of integrated circuits. This paper represents a consensual view of the co-authors, not necessarily in total agreement across all subjects, but in complete agreement on the fundamentals of dimensional metrology in this application. Fundamental expectations in the conventional comparison-based metrology of width are reviewed, with its reliance on calibration and standards, and how it is different from metrology of pitch and image placement. We discuss the wealth of a priori information in an image of a feature on a mask or a wafer. We define the estimates of deviations from these expectations and their applications to effective detection and identification of the measurement errors attributable to the measurement procedure or the metrology tool, as well as to the sample and the process o fits manufacture. Although many individuals and organizations already use such efficient methods, industry-wide standard methods do not exist today. This group of professionals expects that, by placing de facto standard methodologies into public domain, we can help reduce waste and risks inherent in a "spontaneous" technology build-out, thereby enabling a seamless proliferation of these methods by equipment vendors and users of dimensional metrology. Progress in this key technology, with the new dimensional metrology capabilities enabled, leads to improved performance and yield of IC products, as well as increased automation and manufacturing efficiency, ensuring the long-term health of our industry.