Effect of conditioner disc wear on frictional, thermal, kinetic and pad micro-textural attributes of interlayer dielectric and tungsten chemical mechanical planarization

Abstract

A brand-new conventional diamond disc was subjected to 32 h of wear during which SEM images of active diamonds were taken, and pad cut rates (PCRs) were measured. Interlayer dielectric (ILD) wafers were polished before, midway through, and after the wear test (on a brand-new pad) at several values of polishing pressure and pad-wafer sliding velocities. Tungsten wafers were also polished midway through and after the 32 h wear. Polishing was accompanied by pad surface topography analysis via confocal microscopy. The disc experienced significant diamond tip micro-wear along with dried slurry accumulation on its substrate, causing the PCR to drop by a factor of 2. Despite this drastic change, over the duration of the wear test, there were no substantial changes in pad micro-texture, nor ILD or tungsten removal rates indicating the lack of any correlation between PCR and film removal rate during the first 32 h of wear.