Dispersion Number Studies in Chemical Mechanical Planarization

Ara Philipossian, Erin Mitchell

Research output: Contribution to journalConference articlepeer-review


This study explores aspects of the fluid dynamics of CMP processes. The residence time distribution of slurry under the wafer is experimentally determined and used to calculate the Dispersion Number (Δ) of the fluid in the wafer-pad region based on a dispersion model for non-ideal reactors. Furthermore, lubrication theory is used to explain flow behaviors at various operating conditions. Results indicate that at low wafer pressure and high relative pad-wafer velocity, the slurry exhibits nearly ideal plug flow behavior. As pressure increases and velocity decreases, flow begins to deviate from ideality and the slurry becomes increasingly more mixed beneath the wafer. These phenomena are confirmed to be the result of variable slurry film thicknesses between the pad and the wafer, as measured by changes in the coefficient of friction (COF) in the pad-wafer interface.

Original languageEnglish (US)
Pages (from-to)193-197
Number of pages5
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 2003
EventChemical-Mechanical Planarization - San Francisco, CA, United States
Duration: Apr 22 2003Apr 24 2003

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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