Tutorial: Metrology and Instrumentation for Semiconductor Industry

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Metrology and Instrumentation for Semiconductor Industry

Wei-En Fu

Center for Measurement Standards, Industrial Technology Research Institute; Taiwan, ROC



According to recent investigation by IBM and GlobalFoundries, the number of steps required for metrology measurement and defect inspection continues to grow. Generally, two types of metrology measurement tools existing in-line workhorse for CD measurements are CD-SEM (image-based technique) and OCD (model-based technique). However, as the N10/N7 technology nodes approaching, both tools faces significant challenges to assure measurement accuracy and precision required for manufacturing the new device architectures with the FinFET device. The demands for precisely measuring and monitoring the 3D FinFET structural measurement parameters such as sidewall angle, height, top round corner and undercut are significantly increased. Transmission small angle X-ray scattering (tSAXS) has been identified as a potential solution for measuring nanoscale 3D structures in an ITRS roadmap. Among these 3D features, average CDs, such as pitch and pitch variations, can be obtained straightforwardly by the spacing of diffraction peaks. Other profile related CDs, such as linewidth, line edge roughness, line width roughness, pitch walking, film thicknesses on sidewalls, can be modeled and extracted from the envelope function of the scattering intensity based on simple mathematical models. tSAXS has mostly been performed using a synchrotron X-ray source for its high beam flux or high brilliance which enables tSAXS measurements of samples with a minuscule scattering volume. However, synchrotron sources are simply too large and too expensive for daily industrial deployment. A laboratory system with a Mo rotating anode X-ray source has been successfully demonstrated for tSAXS applications, but the measurement speed is too slow for many real world applications such as process control in IC fabrications. In this work, a technique to provide enhancements of the X-ray scattering intensity is discussed using a line grating as the demonstration target (the structures of interests). By positioning an enhancement grating within the longitudinal coherence length from the target grating the scattering intensity is expected to increase; the extent of increase depends on the distance between the enhancement and the target gratings and the scattering angle as well.


Deputy Division Director and Principal Researcher

National Measurement Laboratory            

Center for Measurement Standards, Industrial Technology Research Institute


  • Nanoscale Metrology and Science
  • Thin Film Stress Characterizations
  • X-Ray Technology
  • Micro/Nano-Machining for Advanced Materials


B.S.            Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan. 1990

M.S.           Mechanical Engineering, University of Connecticut, Storrs, CT. 1997

Ph.D.         Industrial and Manufacturing Engineering, Pennsylvania State University,                                                University Park, PA. 2003


  • R & D Service Excellence Award, Department of Industrial Technology
  • Representative of VAMAS (Versailles Project on Advanced Materials and Standards) Steering Committee