3511 Study on ultra-planarization process using poly-hydroxylated fullerene

CMP (Chemical Mechanical Polishing), which is a polishing process combining chemical effect by chelating agent and mechanical effect by abrasive particle, is a key technology for multilayered semiconductor. Although colloidal silica is generally used as an abrasive particle of CMP process, the downsizing of particles and the removal of metal contamination are demanded for 45nm design rule. Then we have proposed poly-hydroxylated fullerene as abrasive. Because poly-hydroxylated fullerene has good features such as uniformity of particle size (1nm) and no metal contamination, it is more suitable for abrasive than colloidal silica. However the polishing rate is low (50nm/min) because of small diameter of abrasive. So in order to improve the polishing rate, we have investigated the method of controlling an abrasive size by producing aggregates. The fullerene clusters are produced by UV laser irradiation for aggregates. Consequently, the abrasive size is controllable from 1 to 250nm, and higher polishing rate (Max 300nm/min) is achieved by using fullerene clusters as an abrasive.