Mechanical properties of chemical mechanical polishing pads containing water-soluble particles

Non-porous pads containing varying amounts of embedded water-soluble particles (WSP) have been characterized and compared to porous pads for interlayer dielectric chemical mechanical planarization (CMP) applications. In situ infrared imaging of the pad shows temperatures increasing as a function of pressure and velocity. Results also indicate that pad surface temperatures can increase up to 10 °C for a 1-min polish. Thermal information proves to be a critical component in explaining the viscoelastic response of the pad as a result of CMP process temperatures. Glass transition temperatures for WSP-containing pads occur within standard CMP operating temperatures (20-40 °C). Comparative storage modulus trends demonstrate steeper decreasing slopes with increasing temperature for WSP-containing pads than the IC-1000. The gradually decreasing slope for the IC-1000 is a sign of a highly cross-linked material. WSP-containing pads also exhibit a greater energy loss due to heat as quantified by the difference in tan δ. Regardless of whether a pad is new or used, dynamic mechanical analysis results indicate similar bulk properties.