Patent ID: 8742345

Claim:
A method for detecting an electron beam of a SEM, comprising: providing a detection sample including a plurality of line patterns formed thereon, wherein the plurality of line patterns has a length in a first direction; obtaining a power spectral density (PSD) curve of a standardized model, wherein the standardized model and the detection sample are formed under a same exposure process; obtaining an edge contour of each of the plurality of line patterns of the detection sample by the SEM; sampling the edge contour of each of the plurality of line patterns of the detection sample at a sampling frequency to obtain a variation range at a sampling point on the edge contour in a second direction, the second direction being perpendicular to the first direction; obtaining a PSD curve of the detection sample according to the variation range; and comparing the PSD curve of the detection sample and the PSD curve of the standardized model to calculate an area between the PSD curve of the detection sample and the PSD curve of the standardized model; determining that the electron beam of the SEM has a high quality in the second direction when the area is smaller than or equal to a first preset area, wherein the first preset area is an area between a tool reference PSD curve for the same exposure process and the PSD curve of the standardized model.