Appeal No. 1999-2347
Application 08/892,560
We affirm.
BACKGROUND
The disclosed invention relates to a method for creating
contact vias through an oxide layer to the surface of a buried
metal layer without forming non-conductive back-sputtered metal
compounds on the via sidewalls.
Claim 21, the sole independent claim, is reproduced below.
21. A method of forming a semiconductor device,
comprising:
providing a substrate having a metal pad;
forming a silicon nitride layer over said metal pad;
forming a silicon dioxide layer over said silicon nitride
layer;
first dry anisotropic etching said silicon dioxide layer
to form a via extending through said silicon dioxide
layer to expose a portion of said silicon nitride
layer; and
etching said silicon nitride layer to form a via extending
through the silicon nitride layer to expose a portion
of said metal pad without forming non-conductive
back-sputtered compounds on sidewalls of said via.
THE PRIOR ART
The Examiner relies on the following prior art:
Stocker 4,484,979 November 27, 1984
Balda et al. (Balda) 4,523,372 June 18, 1985
Erie et al. (Erie) 4,717,449 January 5, 1988
Kim et al. (Kim) 4,767,724 August 30, 1988
Barber et al. (Barber) 4,966,870 October 30, 1990
Butler 5,104,822 April 14, 1992
Keller et al. (Keller) 5,338,395 August 16, 1994
Woo et al. (Woo) 5,451,543 September 19, 1995
(filed April 25, 1994)
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