Shortest path CD measurement using contour extraction

A new CD measurement methodology providing automated measurement of diagonal CDs using contour extraction with an e-beam inspection tool is presented. The use of E-beam inspection tools to provide quality CD data at a significantly higher throughput than CD SEM tools, using a methodology called CDU, is well established. The higher throughput is the result of larger field of view and greater sample frequency. More recently, the ability to extract contours (the edges of the pattern at the wafer surface) has been developed. Extraction of the shortest path between shapes is a natural extension combining these two features. Shortest path measurement is most interesting when this path is at a diagonal. Two examples which use this capability are shared. The first is for MOL patterning involving multiple masks for a cutting-edge FINFET technology. The second is for BEOL patterning for a cutting-edge fully depleted silicon-on-insulator (FDSOI) technology.