Effects of electron‐beam parameters on critical‐dimension measurements

One of the important requirements for critical‐dimension scanning electron microscopes is to improve the reproducibility of measurement in response to the scaling of features on semiconductor devices. A reproducibility of 3 nm, about 1/100 of the minimum pattern size, will be required for the next generation subquarter‐micron devices. It is clear that the sampling pitch, incident angle, and blurring of the electron beam produce measurement errors in the order of a few nm and the precise control of these parameters is necessary, but not sufficient for achieving a reproducibility of 3 nm.