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MechanicalModeling of the 2D Interfacial Slurry Pressure in CMP

Published online by Cambridge University Press:  01 February 2011

C. Fred Higgs III ,
Sum Huan Ng ,
Inho Yoon ,
Lei Shan ,
Lipkong Yap  and
Steven Danyluk
C. Fred Higgs III
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
Sum Huan Ng
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
Inho Yoon
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
Lei Shan
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
Lipkong Yap
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
Steven Danyluk
Affiliation:
The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlanta, GA. 30332-0405
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Abstract

Chemical mechanical polishing (CMP) is a manufacturing process used to remove or planarize metallic, dielectric, or barrier layers on silicon wafers. During polishing, a wafer is pressed against an elastic pad that is flooded with slurry. Prior work has shown that an asymmetrical, subambient pressure develops at the interface between the silicon and the pad during polishing. Since the slurry pressure is on the order of the wafer-on-pad contact stress, the total contact pressure is asymmetrical. This promotes a non-uniform polishing rate, since Preston's equation states that the material removal rate is proportional to the total contact pressure. In order to determine the total contact pressure, experiments were conducted to measure the two-dimensional fluid pressure. A superposition method was then employed to calculate the slurry film thickness by performing an equilibrium analysis of the forces and moments created by the fluid and solid interactions. The film thickness obtained by this method is used to model the slurry pressure using the polar Reynolds' equation. Modeling results qualitatively agree with experiments.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 767: Symposium F – Chemical-Mechanical Planarization , 2003 , F7
Copyright
Copyright © Materials Research Society 2003

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