Nanoscale Resist-Pattern Defects Clustered in the Micron Region Found by Soft X-ray Microscopy

The causes of pattern defects are diverse, and it is difficult to find their causes immediately, thus further information collection is necessary. Therefore, we attempted to determine the causes of pattern defects by observing pattern defects in the resist pattern state. In this study, resist pattern observation was performed using both soft X-ray microscope and atomic force microscope. The soft X-ray microscope was a microscope with reflective-magnification-projection optics. The photon-energy band was 280-300 eV near the carbon K absorption edge. Contrast images corresponding to the chemical-bonding state of carbon were obtained in this energy band region. Pattern defects were successfully detected from the contrast image. The surface topography was observed by atomic force microscopy. The defects were found to be nanoscale resist-pattern defects clustered in the micron region. The results of the resist observation were then comprehensively discussed to estimate the defect-generation process. The results provided suggestive information for the defect reduction.