SEM-based System For Calibration Of Linewidth SRMs For The IC industry

The National Bureau of Standards is currently developing a new scanning electron microscope-based linewidth measurement system for future calibration of standard reference materials for the IC industry. This system incorporates a piezo/interferometric stage for precise translational motion and the monitoring of distance, improved vibration-isolation, microprocessor stage control system, and computer data analysis. The specifications incorporated into the system are designed for the measurement of linewidth dimensions from 0.1 to 2 μm with a precision of 0.002 μm. The design philosophy of the system is discussed along with the current limitations of accurate edge detection in SEM-based systems.