Material Removal Mechanism in CMP: A Comprehensive Model of Abrasive Particle, Pad Asperity and Wafer Interactions

  • Jianfeng Luo
  • David A. Dornfeld

Abstract

The CMP process has been widely accepted in the semiconductor industry for oxide dielectric and metal layer planarization [3.1]. It is used to insure that the interconnects between multi-layer chips are achieved reliably and that the thickness of dielectric materials is uniform and sufficient. During CMP processes, a wafer is rotated about its axis while being pressed facedown by a carrier and a carrier film against a polishing pad/belt covered with colloidal silica slurry with specific chemical properties. The abrasive slurry, composed of, for example, 50–70 nanometer fused silica in an aqueous solution with pH between 8.5–11, plays an important role in the material removal mechanism in CMP. Microscopic observations of polished surfaces have shown that material removal in CMP occurs as a consequence of a combination of chemical reaction of the slurry chemicals with the wafer surface materials and the repeated sliding, rolling or indentation of the abrasive particles against the wafer surface [3.2]. Most analyses of the mechanism of CMP treat the chemical effects and mechanical effects of the slurry separately. In this chapter, we focus on studying the mechanical effect.

Keywords

Brittle Tungsten Stein Polyurethane Sten 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Jianfeng Luo
    • 1
  • David A. Dornfeld
    • 2
  1. 1.R & D Cypress SemiconductorSan JoseUSA
  2. 2.Dept. Mechanical EngineeringUniversity of California at BerkeleyBerkeleyUSA

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