Appeal No. 2001-2182 7
Application No. 08/948,895
material layer may be most preferably silicon nitride. See column 3, lines 36-38.
Accordingly, in the alternative rejection, Sandhu discloses the claimed element of
“depositing silicon nitride or silicon oxynitride on internal surfaces of a deposition
chamber.”
Thereafter Shankar is relied upon for the disclosure of a barrier layer which includes
TiN. See column 3, lines 47-49. A lower barrier layer of TiN is formed over an oxide
layer. See column 3, lines 38-39. See Figure 1. The multilayer formation includes lower
barrier layer 40, aluminum base metal 50 and upper barrier layer 60. See column 6, lines
1-2. The upper barrier layer may be formed from the same material as the lower barrier
layer, i.e., TiN. See column 5, lines 29-32. Moreover, a Ti/TiN barrier layer is disclosed
as being preferred because, “the titanium metal layer below the titanium compound or
alloy will adhere well to both the exposed silicon where the electrical contact is to be made
as well as to the adjacent oxide layer.” See column 4, lines 7-16.
The examiner admits that EP’283, “does not disclose depositing an adhesive layer
such as TiN layer on the substrate prior to depositing the fluorinated amorphous carbon.”
See Answer, pages 5 and 9. In view of the teachings of Shankar however, the examiner
concludes that, “it would have been obvious to have deposited lower and upper TiN
barrier layers around the aluminum lines of EP 701283 because doing so would have been
expected to have prevented diffusion of aluminum into the silicon substrate and improved
the electromigration resistance of the wiring line.” See Answer, pages 5, 9 and 10.
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