[Table of Contents]

Plasma and Fusion Research

Volume 3, 051 (2008)

Letters

Dechuck Operation of Coulomb Type and Johnsen-Rahbek Type of Electrostatic Chuck Used in Plasma Processing
Gyu Il SHIM and Hideo SUGAI1)
Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603, Japan
1)
Department of Electronics and Information Engineering, Chubu University, Kasugai 487-8501, Japan
(Received 17 June 2008 / Accepted 24 July 2008 / Published 19 September 2008)

Abstract

Comparative study on Coulomb type and Johnsen-Rahbek type of electrostatic chuck used for holding a silicon wafer in plasma processing is presented. The remarkable differences between the two types are found in dechuck operation where a high voltage applied to the chuck electrode is turned off to release the wafer from the chuck stage. In case of the Coulomb type, an instantaneous large short-circuit current flows exponentially decreasing with a short time constant (τ = 0.14 ms). In case of the J-R type, a non-exponentially decaying small current is sustained for much longer time (∼1000 ms), thus giving rise to the considerable delay of wafer dechuck. The mechanism of such decay is explained by a microscopic bi-layer model where the interfacial layer is divided into three distinct regions having their own capacitance and surface resistance.

Keywords

electrostatic chuck, Johnsen-Rahbek effect, electrostatic dechuck, surface resistivity, bi-layer model

DOI: 10.1585/pfr.3.051

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References

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This paper may be cited as follows:

Gyu Il SHIM and Hideo SUGAI, Plasma Fusion Res. 3, 051 (2008).