X-ray metrology for advanced microelectronics

The recent development of bright X-ray sources, reliable X-ray focusing optics, large X-ray detectors and X-ray data modelling and processing, have improved X-ray techniques to the point where many are being introduced in MOS transistor manufacturing lines as new metrology methods. The fundamental X-ray physical properties, such as their small wavelength and their weak interaction with solid-state matter satisfy basic in-line metrology requirements: non-destructiveness, speed, accuracy, reliability and long-term stability. The capability of X-ray based metrology methods to monitor critical 65 and 45 nm processes such as ion implant, nitrided SiO2 gate dielectrics, NiSi, Cu/porous low-kappa interconnects and MIM capacitors is highlighted in this paper.