Patent ID: 6909092

Claim:
An electron beam apparatus comprising: an electron beam source for irradiating a sample with a primary electron beam, said sample including a pattern structure on the surface consisting of complex materials including a mixture of a metal and an insulating material; an optical mapping system for imagining secondary electrons emitted from the surface of said sample irradiated with the primary electron beam; a detector for detecting said secondary electrons; and an image processing system for processing a signal from said detector to compare an image with an adjacent image and form an electron image, thereby detecting defects for classification and discrimination, wherein said primary electron beam is optimized to have a beam energy in a range of 2 to 4 KeV, thereby reducing a secondary electron emission efficiency from the sample to less than one and causing the sample to be negatively charted to reduce image distortions, and wherein said electron beam source illuminates the sample before a material inspection to reduce potential difference between said metal material and insulating material.