Papers by Author: Taeho Ha

Abstract: This paper presents a laser-assisted Cu-CMP (Chemical Mechanical Polishing) method for obtaining higher planarized surface by forming laser aggregation particles on recessed areas of uneven copper surface before polishing. At first, the laser trapping of fine particles in slurry and the formation of aggregated marks on the copper wafer surface were investigated by fundamental experiments based on optical radiation pressure. Next, proposed planarization method for uneven surface of copper wafer was attempted. As the polishing processed, the height of aggregated marks was reduced. Then, it was confirmed that the aggregated marks played a role of masks, and no material removal at the bottom surface of recessed areas took place during polishing. This process made it possible to realize high planarity on copper wafer surface.

Abstract: Laser scattering characteristics of typical CMP-induced defects such as particles and microscratches with the size of sub-micron order are investigated using a developed automated scattered light measurement system. The measurement system has an ability to detect three-dimensional distribution of scattered light from the defects with high sensitivity. The angular distributions of scattered light from the standard PSL (Polystyrene latex) spheres and microscratches reveal that scattering characteristics of microscratches are quite different from those of Particles. The scattered light from the PSL sphere is detected mainly ahead. In contrast, the scattered light from the microscratches only exists in the direction perpendicular to its length dimension at an oblique incidence maintaining the sheet-shaped pattern, even if its orientation relative to the incident direction is changed. Optical arrangement for defect detection and classification is suggested based on the experimental results.