Soft metal conductor
AssigneeInternational Business Machines Corporation
InventorsRajiv Vasant Joshi, Manu Jamnadas Tejwani
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Abstract
A soft metal conductor for use in a semiconductor device that has an upper-most layer consisting of grains having grain sizes sufficiently large so as to provide a substantially scratch-free surface upon polishing in a subsequent chemical mechanical polishing step.
Claims20
A soft metal conductor comprising an upper-most layer consisting of grains capable of providing a substantially scratch-free planar surface upon polishing in a subsequent chemical mechanical polishing step, said soft metal is selected from the group consisting of Al, Cu, Ag, binary and ternary alloys of Al, Cu and Ag.
A soft metal conductor having improved hardness in its upper-most layer for use in a semiconductor device wherein said upper-most layer consists of grains having grain sizes not smaller than about 20% of the thickness of said soft metal conductor, said soft metal is selected from the group consisting of Al, Cu, Ag, binary and ternary alloys of Al, Cu and Ag.
An electrically conducting soft metal structure for use in a semiconductor device comprising:
- an upper-most layer consisting of grains having grain sizes not smaller than about 20% of the thickness of said soft metal structure,
- a second layer contiguous with and immediately adjacent to said upper-most layer consisting of grains having grain sizes not larger than about 20% of the thickness of said soft metal structure, and
- said soft metal in said soft metal structure is selected from the group consisting of Al, Cu, Ag, binary and ternary alloys of Al, Cu and Ag.
A soft metal conductor for use in a semiconductor device comprising:
- a first soft metal layer selected from the group consisting of aluminum copper, silver binary and ternary alloys of aluminum, copper and silvers
- a first Ti layer of less than 30 nm thick on top of said first soft metal layer,
- a second soft metal layer on top of said first Ti layer having in its upper-most surface metal grains of grain sizes not smaller than about 20% of the thickness of said second soft metal layer, said second soft metal is selected from the group consisting of Al, Cu, Ag, binary and ternary alloys of Al, Cu and Ag, and
- a second Ti layer on top of said second soft metal layer;
- whereby at least said first Ti layer sandwiched between two soft metal layers is converted to TiAl3 upon annealing at a temperature higher than room temperature such that diffusion of atoms of said soft metal through said TiAl3 film occurs upon the passage of an electrical current therethrough and thus improving the electromigration resistance of said soft metal conductor.
Dependencies are inferred from the claim text.