Appeal No. 1998-2671
Application No. 08/480,543
The claimed invention relates to a method for fabricating
interlevel contacts in semiconductor integrated circuit devices
providing for formation of a contact opening through an
insulating layer. A layer of refractory metal is deposited over
the insulating layer and within the opening. An aluminum layer
is then deposited on the refractory metal layer at a temperature
sufficient to cause the aluminum to alloy with the refractory
metal to form an aluminum/refractory metal alloy interface layer.
Appellants assert at pages 9 and 10 of the specification that,
since the formed alloy has a volume greater that the aluminum and
refractory metal separately, the contact opening is filled to a
greater extent than with previous techniques, thereby improving
the planarity of the upper surface of the aluminum layer.
Representative independent claim 10 is reproduced as
follows:
10. A method for fabricating interlevel contacts in an
integrated circuit, comprising the steps of:
forming an opening in an insulating layer to expose a
conductive region beneath;
depositing a refractory metal layer over the insulating
layer and within the opening; and
depositing aluminum at a temperature sufficient to cause the
aluminum to alloy with the refractory metal at an interface
thereof during deposition, wherein the alloy of aluminum and
refractory metal has a volume greater than the aluminum and
2
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