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

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

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

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)
JournalJournal of the Electrochemical Society
Volume153
Issue number9
DOIs
Publication statusPublished - 2006

    Fingerprint

ASJC Scopus subject areas

  • Electrochemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this