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Etch Resistant Coating for Electron Cyclotron Resonance Windows and Liners

IP.com Disclosure Number: IPCOM000122094D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 56K

Publishing Venue

IBM

Related People

Hodgson, RT: AUTHOR [+2]

Abstract

Disclosed is a method of reducing the erosion of the window through which microwave energy is transmitted into an electron cyclotron resonance (ECR) or similar high density plasma. Erosion of the quartz liner which is typically used in the resonance region of these systems is also a problem. The problem is due to the fact that the potential of the plasma is typically 20-30 Volts above ground, and ions leave the bulk of the plasma and bombard the top window and the liner of the ECR source with energies greater than the threshold energy of sputtering. Erosion of the window and/or the liner material results and has two major disadvantages. First, since the microwave window or the liner are rapidly etched, they have to be frequently changed, which results in system down-time and expense.

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Etch Resistant Coating for Electron Cyclotron Resonance Windows and
Liners

      Disclosed is a method of reducing the erosion of the window
through which microwave energy is transmitted into an electron
cyclotron resonance (ECR) or similar high density plasma. Erosion of
the quartz liner which is typically used in the resonance region of
these systems is also a problem. The problem is due to the fact that
the potential of the plasma is typically 20-30 Volts above ground,
and ions leave the bulk of the plasma and bombard the top window and
the liner of the ECR source with energies greater than the threshold
energy of sputtering.  Erosion of the window and/or the liner
material results and has two major disadvantages. First, since the
microwave window or the liner are rapidly etched, they have to be
frequently changed, which results in system down-time and expense.
Second, oxygen, silicon, and aluminum (the elements making up the
window and liner components) are sputtered into the gas phase,
contaminate the plasma and interfere with processing, e.g., reduce
etch selectivity or cause micromasking effects.

      We have previously found that Sc2O3 films, deposited by
sputtering, etch at a much slower rate than SiO2 and/or Al2O3 films
in CF4 plasmas for all the power conditions investigated.  Our etch
rate data show that the etch rate of Sc2O3 is at least by a factor
of 10-100 slower than that of Al2O3 . The same etch rate ratio holds
for high bias conditions (greate...