Diamond structure-dependent pad and wafer polishing performance during chemical mechanical polishing

Abstract

A diamond conditioner is one of the essential components in the maintenance of surface roughness of a pad during chemical mechanical polishing (CMP). In this paper, four different types of diamond conditioner were evaluated for the pad wear rate (PWR) and the material removal rate (MRR) during the pad conditioning and the wafer polishing ex situ. The experiment results revealed that the pad conditioning is strongly dependent on the diamond orientation as compared to grit size and pitch. It is observed that the PWR for “C type” conditioners is about 0.3 mm/h which is higher than that of “N type” diamond conditioner. The COF of “N type” diamond conditioner has the lowest value of ~0.56. The MRR using pad treated by “N type” diamond conditioner is approximately 3500 A/min, which is about 1.6 times higher than that of C1-type diamond conditioner which has same diamond grit size and pitch.