Emerging three-dimensional (3D) transistor structures have increased the demand for an easy and practical method to
measure pattern feature metrics (such as CD, line-edge roughness, etc.) as a function of height (z coordinate). We have
examined 3D pattern-profile extraction from a top-view image obtained using a critical-dimension scanning electron
microscope (CD-SEM). An atomic force microscope (AFM) was used to measure 3D pattern profiles as a reference. In
this examination, line-edge positions were firstly obtained from a CD-SEM image at various threshold levels, and the
result was compared with the reference profile measured using the AFM. From this comparison, a mapping function
from threshold levels of CD-SEM image-processing to z coordinates is obtained. Using this mapping function, 3D
pattern profiles were reconstructed from CD-SEM signal profiles, and the obtained profiles were similar to the directly
obtained cross-sectional profile. Put simply, a 3D pattern-profile was extracted from a top-view image successfully.
Though the results are not sufficient to confirm the validity of our method yet, the method may feasibly be introduced
for quick and easy 3D measurement.