Translator Disclaimer
10 April 2013 Material contrast based inline metrology: process verification and control using back scattered electron imaging on CD-SEM
Author Affiliations +
The Critical Dimension Scanning Electron Microscope (CDSEM) is the traditional workhorse solution for inline process control. Measurements are extracted from top-down images based on secondary electron collection while scanning the specimen. Secondary electrons holding majority of detection yield. These images provide more on the structural information of the specimen surface and less in terms of material contrast. In some cases there is too much structural information in the image which can irritate the measurement, in other cases small but important differences between various material compounds cannot be detected as images are limited by contrast information and resolution of primary scanning beam. Furthermore, accuracy in secondary electron based metrology is limited by charging. To gather the exact required information for certain material compound as needed, a technique, known from material analytic SEM´s has been introduced for inline CDSEM analysis and process control: Low Loss Back Scattered Electron Imaging (LL-BSE). The key at LL-BSE imaging is the collection of only the back scattered electrons (BSE) from outermost specimen surface which undergo the least amount possible of energy loss in the process of image generation following impact of the material by a primary beam. In LL-BSE very good and measurable material distinction and sensitivity, even for very low density material compounds can be achieved. This paper presents new methods for faster process development cycle, at reduced cost, based on LL-BSE mass data mining instead of sending wafers for destructive material analysis.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Carsten Hartig, Daniel Fischer, Bernd Schulz, Alok Vaid, Ofer Adan, Shimon Levi, Adam Ge, Jessica Zhou, Maayan Bar-Zvi, Ronny Enge, and Uwe Groh "Material contrast based inline metrology: process verification and control using back scattered electron imaging on CD-SEM", Proc. SPIE 8681, Metrology, Inspection, and Process Control for Microlithography XXVII, 868108 (10 April 2013);

Back to Top