High magnesium content copper magnesium alloys as diffusion barriers
AssigneeNovellus Systems, Inc.
InventorsRonald A. Powell, Sridhar K. Kailasam, E. Derryck Settles, Larry R. Lane
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Abstract
The present invention pertains to systems and methods for simultaneously producing a diffusion barrier and a seed layer used in integrated circuit metallization. This is achieved by initially depositing copper-magnesium (Cu—Mg) alloys with relatively high levels of Mg (>10 atomic %, which is equivalent to about >4 weight %). After the alloys are deposited, they self-form a magnesium oxide (MgO) based barrier layer at the substrate interface, thus eliminating the need for a separate operation for barrier deposition. The migration of Mg to the substrate interface leaves the remainder of the film relatively pure Cu.
Claims20
A method of forming, from a single copper alloy layer, a self-forming diffusion barrier layer and a copper seed layer, the method comprising:
- depositing the single copper alloy layer on a dielectric material, wherein the single copper alloy layer comprises at least 12.5 atomic percent magnesium or greater and whereby at least a portion of the magnesium in the single copper alloy layer can react with the dielectric material and thereby form the self-forming diffusion barrier layer at an interface between the single copper alloy layer and the dielectric material.
Dependencies are inferred from the claim text.