Loading

  • Francis F. Chen
  • Jane P. Chang

Abstract

It is generally observed that in a plasma etching process the etching rate drops as the etching area exposed to the plasma increases. This decrease in etching rate is true for processes that consume a major portion of the reactive species created in the plasma. Processes that are limited by the surface reaction kinetics do not exhibit this behavior. In processes where a loading effect is observed, the etching rate is typically proportional to the concentration of the reactant. For the case of etching m wafers with a plasma that produces single etching species, the loading effect is given as
$$ {{{R_o}} \over {{R_m}}} = 1 + m\phi = 1 + {{{A_w}{k_w}} \over {A{k_s}}} $$
(1)
where Ro is the etch rate in an empty reactor, Rm is the etch rate with m wafers present. Note that A and Aw are areas of the reactor surface and a wafer respectively, while kw and ks are the rate coefficients for reactant recombination at the reactors surfaces and of the reaction at the wafer respectively. Therefore ϕ is the slope of the loading curve as shown schematically in Fig. 26.

Keywords

Dioxide Recombination Chlorine Polysilicon 

Copyright information

© Springer Science+Business Media New York 2003

Authors and Affiliations

  • Francis F. Chen
    • 1
  • Jane P. Chang
    • 2
  1. 1.Electrical Engineering DepartmentUniversity of CaliforniaLos AngelesUSA
  2. 2.Chemical Engineering DepartmentUniversity of CaliforniaLos AngelesUSA

Personalised recommendations