Full-field Thermal Deformation Measurements in a ScanningElectron Microscope by 2D Digital Image Correlation

摘要

Using recently developed methods for applicationof a nano-scale random pattern having high contrast duringSEM imaging, baseline full-field thermal deformation experi-ments have been performed successfully in an FEI QuantaSEM using 2D-DIC methods. Employing a specially rede-signed commercial heating plate and control system, withmodified specimen attachment procedures to minimizeunwanted image motions, recently developed distortioncorrection procedures were shown to be effective in removingboth drift and spatial distortion fields under thermal heating.2D-DIC results from heating experiments up to 125°C on analuminum specimen indicate that (a) the fully correcteddisplacement components have nearly random variabilityand a standard deviation of 0.02 pixels (≈25 nm at 200x and≈0.5 nm at 10,000x) in each displacement component and (b)the unbiased measured strain fields have a standard deviation≈150 X 10~(-6)and a mean value that is in good agreement withindependent measurements, confirming that the SEM-DICbased method can be used for both micro-scale and nano-scale thermal strain measurements.