Stepper Lens Characterization Using A Field Emission SEM

A method of stepper lens evaluation has been developed which utilizes a simple resolution test pattern of the type usually supplied with the stepper. Measurements are made using an automated field emission SEM equipped to perform whole wafer non-destructive critical dimension analysis. Measurement data on focus and sizing is then analyzed by a computer program easily run on a small personal computer. Information on reticle sizing errors and wafer flatness may also be included in the analysis to minimize errors.