| 摘要 |
A microscopic length scale typically about 50 mu m long and graduated in several intervals ranging from 1 mu m to 20 mu m. The scale is useful in calibrating the magnification of scanning electron microscopes (SEMs) and other electron imaging instruments. The scale comprises alternating layers of two metals deposited on a substrate. The two metals have substantially different electron emission coefficients to provide contrasting emission signals when scanned by an electron beam. One of the metals, preferably gold, is deposited in uniform layers about 40-80 nm thick. The other metal, preferably nickel, is deposited in several layers ranging from 1 mu m or so thick near the substrate to 20 mu m thick in the outermost layer. The resultant multilayer composite is cut into one or more samples and each sample is mounted on edge. The exposed edge is ground and metallographically polished and a microscopic indentation is made in the substrate near the first gold layer. The indentation defines a reference region, and the distances between the first gold layer and the subsequent gold layers in the reference region are measured. The measurement is made using a similar sample which was previously calibrated with the aid of a polarizing laser interferometer. |
