Appeal No. 2004-0859
Application 08/866,456
upwardly from the first conductive layer and the upper portion is
bowled upwardly and outwardly from the lower portion to the upper
surface of the insulating layer. In claim 39 the lower portion
has a diameter adjacent the conductive layer which is smaller
than the diameter of the upper portion at the surface of the
insulating layer. In claim 44 the lower portion has a steeper
side wall than the upper portion.
For the appellant’s claim requirement of an insulating layer
having an opening with a lower portion and a larger-diameter
upper portion, the examiner relies (answer, pages 5-8) upon Sato
which discloses a first conductive layer (lower wire 12) having
thereover an insulating layer (13) with an opening therethrough
(col. 4, line 67 - col. 5, line 45). The opening has a lower
portion adjacent the substrate and a larger-diameter upper
portion (figure 4D). These portions are formed by two successive
lithographic processes which are not described (col. 5, lines 2-
7). The disclosed benefit of these portions is that even if an
adhesion layer (15) which lines the opening, and a blanket
tungsten layer (16) which fills the opening, are overetched when
they are etched back, the overetching does not extend downwardly
beyond the upper, wider portion of the opening (col. 5, lines 39-
42). Hence, “[t]he metal plug 16A thus formed is highly
4
Page: Previous 1 2 3 4 5 6 7 8 9 Next
Last modified: November 3, 2007