Local-distortion of CD-SEM image can be detected and compensated by a unique technique: View-Shift method. As
design rule of semiconductor device is getting shrunk, metrology by critical dimension scanning electron microscope
(CD-SEM) is not only for measuring dimension but also shape, such as 2D contour of hot-spot pattern and OPC
calibration-pattern. Accuracy of the shape metrology is dependent on the local image-distortion that consists of two
components: magnification distortion and shape distortion. The magnification distortion can be measured by pitchcalibration
method, that measures pitch of an identical line pattern at a lot of locations in image. However, this method
cannot measure the shape distortion, that is for instance, bending of a uniform-width line.
To measure accurately and quickly the image-distortion, we invented the View-Shift method, in which images of uniquetexture
sample are taken before and after an image-shift by about 100nm. Between the two images we measure
displacements of the unique-textures found at each grid-point spread over the image. Variation of the local displacements
indicates the local image-distortion. In this work, we demonstrate a method to compensate the image-distortion detected
by the View-Shift method. Due to the image-distortion, edge-points determined in SEM-image have already been
dislocated. Such dislocation can be relocated to compensate the detected local-distortion. Onsite and on-demand
compensation right before CD-SEM measurement for process monitoring is possible because we can quickly apply the
View-Shift method and complete the compensation in a few minutes.