Investigation of pad staining and its effect on removal rate in copper chemical mechanical planarization

H. Lee, Y. Zhuang, L. Borucki, S. Joh, F. O'Moore, Ara Philipossian

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

In copper chemical mechanical planarization process, stains are often generated on the pad surface due to the build-up of polishing by-products. Pad staining is a major concern because it might affect defect, non-uniformity across the wafer, and removal rate variation during polishing. In this study, the characteristics of stains formed on an IC1000 XY grooved pad obtained under various polishing conditions were investigated. In addition, wafers were polished on an IC1000 plain pad to determine the effect of hydrodynamic pressure on staining pattern. Experiments were performed on a table-top axisymmetric polishing system consisting of a 300-mm non-rotating platen and 100-mm rotating wafers. Stains were successfully generated on the pad surface and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the stains contained copper polishing by-products. As the stains deposited on the pad land areas were darker in the direction of wafer rotation as well as in the pad radial direction, it was believed that staining agents were produced during polishing and subsequently advected downstream by the slurry flow. Although staining increased with polishing pressure, wafer rotation rate, polishing time and slurry flow rate, it did not seem to affect removal rate. The white light interferometric analysis indicated that the stains did not physically change the pad surface topography. It was observed that the hydrodynamic pressure significantly impacted the staining pattern on an IC1000 plain pad.

Original languageEnglish (US)
Pages (from-to)259-264
Number of pages6
JournalThin Solid Films
Volume519
Issue number1
DOIs
StatePublished - Oct 29 2010

Fingerprint

Chemical mechanical polishing
staining
Polishing
polishing
Copper
copper
Coloring Agents
wafers
Byproducts
plains
Hydrodynamics
hydrodynamics
platens
Surface topography
nonuniformity
X ray photoelectron spectroscopy
Flow rate
topography
flow velocity
photoelectron spectroscopy

Keywords

  • Chemical mechanical planarization
  • Copper removal rate
  • Hydrodynamic pressure B
  • Pad staining
  • Pad surface topography

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Investigation of pad staining and its effect on removal rate in copper chemical mechanical planarization. / Lee, H.; Zhuang, Y.; Borucki, L.; Joh, S.; O'Moore, F.; Philipossian, Ara.

In: Thin Solid Films, Vol. 519, No. 1, 29.10.2010, p. 259-264.

Research output: Contribution to journalArticle

Lee, H. ; Zhuang, Y. ; Borucki, L. ; Joh, S. ; O'Moore, F. ; Philipossian, Ara. / Investigation of pad staining and its effect on removal rate in copper chemical mechanical planarization. In: Thin Solid Films. 2010 ; Vol. 519, No. 1. pp. 259-264.
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