A. Takafuji et al., Development of a secondary-electron detection system for high-speed high-sensitivity inspection SEM imaging, MICROEL ENG, 53(1-4), 2000, pp. 649-652
Electron optics and secondary-electron (SE) detection systems that increase
the speed and sensitivity of SEM imaging systems used for inspecting semic
onductor devices have been developed. Direct and indirect SE detection syst
ems optimized for retarding electron optics were investigated. In indirect
detection, SEs are deflected to a converter electrode, and a detector colle
cts the SEs generated from the electrode. Simulation of the SE trajectories
showed that indirect systems are capable of stable high-efficiency SE coll
ection at various retarding voltages, V-r. Indirect systems were developed
and found that various V-r can be applied to a sample to achieve stable SE
collection efficiency.