Aluminum-germanium alloys for VLSI metallization
AssigneeInternational Business Machines Corporation
InventorKing-Ning Tu
Life of this patent
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Abstract
An apparatus and method for forming an interconnect through an opening or on an insulation layer with the coefficient of thermal expansion of the interconnect adjusted to reduce the thermal stress between the interconnect and the insulation layer is described incorporating the steps of forming a solid solution of a binary alloy including germanium and aluminum or a ternary alloy including aluminum, germanium and a third element, for example silicon, and forming a precipitate from the solid solution at a reduced temperature with respect to the temperature of forming the solid solution whereby the volume of the precipitate including germanium and the remaining solid solution is larger than the volume of the original solid solution.
Claims26
A method for forming an interconnect through an opening in an insulation layer comprising the steps of:
- depositing aluminum in said opening,
- depositing germanium in said opening with said aluminum,
- raising the temperature of said aluminum and said germanium to a first temperature which is below the melting point of aluminum for a first period of time to allow said germanium to diffuse through said aluminum to provide a volume of a first solid solution of germanium in said aluminum of greater than a first atomic percent number, and
- lowering the temperature of said aluminum and said germanium to a second temperature for a second period of time to allow a portion of said germanium to precipitate out of said first solid solution whereby the total volume of said precipitated germanium and the remaining solid solution is larger than said volume of said first solid solution.
A method for forming an interconnect in contact with an insulation layer comprising the steps of:
- depositing aluminum over said insulation,
- depositing germanium adjacent said aluminum,
- raising the temperature of said aluminum and germanium to a first temperature which is below the melting point of aluminum for a first period of time to allow said germanium to diffuse through said aluminum to provide a first solid solution of germanium in said aluminum of greater than a first atomic percent number, and
- lowering the temperature of said aluminum and germanium to a second temperature for a second period of time to allow a portion of said germanium to precipitate out of said solid solution whereby the volume of the precipitated germanium and the remaining solid solution is larger than the volume of said first solid solution.
Dependencies are inferred from the claim text.