| 摘要 |
A measurement technique for determining the width of a structure on a mask is described. During a focus sweep, the width of the structure on a photomask, and an edge slope thereof or the structure contrast thereof are measured on a scanning electron microscope by controlling a current through a flow in a magnetic lens by a control unit. To determine the best focus, a function is fitted to the measured values for the contrast and the angle of edge inclination and the focus is read off at the extreme value thereof. A further function is adapted to the values, measured in each case as a function of the focus for the structural width, and the functional value relating to the previously determined best focus is determined. |
