Real-time coefficient of friction (COF) analysis is used to identify the tribology of the process and to determine the useful life of the polishing pad as a function of key processing parameters. Results indicate that minor COF changes affect interlayer dielectric (ILD) removal rate and pad life. Slurry flow rate is shown to modulate average COF without altering the tribological mechanism associated with a particular range of Sommerfeld numbers. This finding is used to isolate and study the effect of COF on pad life. Regardless of process tribology, results indicate that pad life is increased with increasing slurry flow rate. Due to the effect of COF on removal rate, the absolute magnitude of ILD removal rate is shown to be highly dependent on the tribological mechanism. The work illustrates the complexities involved in reaching a compromise between removal rate, slurry flow rate, high volume manufacturing, and pad life.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry