Endpoint detection in Cu-CMP detection of Ta layer to low-k layer transition using fluorescence

S. Kondoju, C. Juncker, P. Lucas, S. Raghavan, P. Fischer, A. Oehler, M. Moinpour

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Introduction of low-dielectric constant (k) materials, replacing silicon dioxide, has reduced the time delay (RC delay) and enhanced the performance of integrated circuits (IC) significantly. The two most common ways of depositing these low-k materials are spin-on and chemical vapor deposition. Chemical-vapor-deposited low-k materials use an organic precursor consisting of carbon, hydrogen, and oxygen as the main constituents. Some of these precursors yield a significantly large fluorescence signal when irradiated with an appropriate laser. This signal can be successfully utilized to detect the transition from the barrier layer to dielectric layer in chemical mechanical polishing, which is now typically done using reflectivity measurements in the industry. In this work, sensitivity of the fluorescence technique in detecting the transition is demonstrated and compared with the conventional reflectivity method. An abrasion cell integrated with a spectrometer was used to make the measurements. Capabilities and limitations of the fluorescence techniques are discussed.

Original languageEnglish (US)
Pages (from-to)G830-G833
JournalJournal of the Electrochemical Society
Issue number9
StatePublished - 2006

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Renewable Energy, Sustainability and the Environment


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