Critical dimension metrology for sub-150-nm lithographic films using real-time scatterometry

The measurement of critical dimension for materials intended for use in manufacturing devices with features of 150nm or less is a significant challenge. Currently available metrology is inadequate at providing robust measurements with the precision and accuracy needed to quantify differences. The added challenge needing to understand the impact on process and material changes on profiles further complicates the analysis of the these data. The further challenge of measuring contact holes or vias smaller than 200nm for size and shape as well as profile is an essential but elusive need for all CD metrology. CD Scatterometry shows great promise in meeting the precision and accuracy needs of current and future metrology needs. First generation library-based solutions showed great capability, but were limited in their sensitivity and flexibility. We report here the results of using next generation optical metrology equipment coupled with robust real-time analysis software to measure the critical dimensions on several difficult organic films on production and research levels. Demonstrations of capability and flexibility of measurements of various linewidths and pitches across 248nm and 193nm technologies, as well as contact hole metrology, will be featured. Special focus on sensitivity to material and process variability and intentional changes will be included. Specific examples of production level decision guidance based on real-time critical dimension measurements will also be presented.