99123865B-ENG Abstract: Long-Term Evaluation of the Litmas Blue Plasma Device for Point-of-Use (POU) Perfluorocompound and Hydrofluorocarbon Abatement

SEMATECH DOC ID #: 99123865B-ENG

Title: Long-Term Evaluation of the Litmas Blue Plasma Device for Point-of-Use (POU) Perfluorocompound and Hydrofluorocarbon Abatement

Author(s): Benny Perez;David Graves;Eric Tonnis;Jason Rivers;Laurie Beu;Mark Kiehlbauch;Tab Stephens;Victor Vartanian;

Document date: 05/02/2000

Descriptor(s): perfluorocompounds;point of use abatement;emissions reduction;fourier transform infrared spectroscopy;optical emission spectroscopy;high density plasmas;marathon runs;quadrupole mass spectrometers;

Abstract: This report presents the results of an evaluation of the Litmas "Blue"
inductively-coupled, high density plasma device for long-term operation and
impact on manufacturing processes, foreline pressures, and pump hardware.
The effect of increasing the plasma tube diameter to reduce foreline
pressure was evaluated by determining CF4 destruction and destruction
removal efficiency (DRE) using extractive Fourier transform infrared
spectroscopy (FTIR). A 1050-wafer marathon on blanket I-line photoresist
wafers with 120-second etch steps was conducted to test the unit for
prolonged and repetitive operation. Fluorine emissions were also determined
for CF4/CHF3/Ar and C4F8/CF4/Ar etch recipes using oxygen and water vapor by
quadrupole mass spectrometry (QMS). Determination of byproducts, foreline
pressures, and DRE was performed for C4F8, SF6, and NF3 under a variety of
gas flow conditions with both oxygen and water vapor used as reactive gases.
Experiments to measure hydrogen or water vapor backstreaming through the
turbomolecular pump were conducted by optical emission spectroscopy (OES).
The mechanical pump was disassembled and examined to determine the effect of
prolonged exposure to byproducts of plasma abatement. This revision includes
more precise, updated data.

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