Organic diamond disk versus brazed diamond disk for dressing a chemical–mechanical polishing pad

Abstract

Diamond pad conditioners can be used to determine the efficiency of chemical–mechanical polishing (CMP) processes and the quality of polished wafers. Conventional diamond conditioners such as brazed diamond disks (BDDs) consist of braze-bonded diamond grits. Although conventional diamond conditioners consist of regularly distributed diamond grits, the grit tips are not leveled to the same height. In this research, we evaluated diamond conditioners manufactured using polymer-bonded diamond grits for use in CMP; these conditioners are known as organic diamond disks (ODDs). ODDs are fabricated by reverse casting the substrate. Instead of using a flat substrate as the backing for attaching diamond grits, the substrate is prepared after the diamond grits are leveled on the surface of a mold. The ODD and the BDD were fabricated as circular dressing disks and used in the CMP of dielectric oxide films. Diamond leveling (height distribution of the diamond grits) for the BDD is found to be greater than 50μm. The diamond tips of the ODD are leveled to less than 15μm. The results show that the ODD-dressed pads produce fewer defects in wafers than the BDD-dressed ones. Although the pad dressing rate is lower for the ODD, the wafer removal rate for the ODD is higher than that for the BDD. Hence, the use of ODDs for the mass production of semiconductors can increase not only the lifespan of both the disks and the pads but also the throughput of wafers produced during CMP. Finally, the ODD is processed at room temperature to prevent thermal degradation of its diamond grits.