Appeal No. 2001-2444
Application No. 09/419,176
layer (26), a dielectric layer (27), an etch stop layer (28), a
dielectric layer (30), and a polish assisting layer (31)
(figure 3).1 After a masking layer (33) having a pattern for
forming an interconnect opening (32) has been applied to the
polish assisting layer, the interconnect opening, which includes
an interconnect portion (36) and a plug portion (34) and extends
down to the conductive layer, is formed by etching (col. 5,
lines 33-46; figure 5). The masking layer then is removed and
the interconnect opening is filled with interconnect metal (42)
(col. 6, lines 1-5; figure 6). Because deposition of the
interconnect metal is not selective to deposition in the
interconnect opening alone, the interconnect metal deposits on
top of the polish assisting layer (col. 6, lines 5-8). The
portion of the interconnect metal above the interconnect opening,
and also the polish assisting layer, are removed in a
planarization step, preferably by chemical mechanical polishing,
to form an interconnect (44) inlaid into interlayer
dielectrics 27 and 30 (col. 7, lines 3-40; figure 7). The
1 “The polish assisting layer can include oxides or nitrides of
titanium, tungsten, tantalum, or the like” (col. 8, lines 17-19).
3
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