Ebara Tungsten CMP Process Defect Improvement

Chemical-mechanical planarization (CMP) is mainly used in the manufacture of very large scale integrated circuits (ICs), where global and local planarization of wafers is obtained through chemical and mechanical processes [1]. The CMP process requires a variety of consumables such as chemical, pad, disk, slurry, etc. Slurry is composed of an abrasive and various additives that improve the properties of the CMP process. Tungsten chemical-mechanical planarization (W CMP) has a special mechanism. Due to the high hardness of W, the choice of the hardness of the pad and the particles in the slurry is no longer a priority for the improvement of small scratches, but should focus on the uniformity of the W film and the surface properties of W film after CMP. Therefore, particles such as by-products and slurry residue after planarization should be removed from the surface. However, because nanoparticles have a strong electrostatic attraction to wafers [2], it is difficult to completely remove nanoparticles despite the cleaning process, and contamination remains on the wafer surface. Therefore, this paper mainly studies the improvement methods of polishing and cleaning process to reduce the retention rate of nanoparticles.