Variable doping of metal plugs for enhanced reliability
First Claim
1. A method of fabricating an interconnect comprising the steps of:
- (a) providing a first layer of electrically conductive interconnect;
(b) forming a via defined by walls extending to said first layer;
(c) forming a first layer of electrically conductive metal on the walls of said via having a predetermined etch rate relative to a specific etch species; and
(d) forming a second layer of electrically conductive metal on said first layer having an etch rate relative to said specific etch species greater than said first layer.
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Accused Products
Abstract
A method of fabricating an interconnect wherein there is initially provided a first layer of electrically conductive interconnect (3). A via (7) is formed which is defined by walls extending to the first layer of interconnect. A layer of titanium (9) is formed between the electrically conductive interconnect and the first layer of electrically conductive metal (11). A first layer of electrically conductive metal is formed on the walls of the via having a predetermined etch rate relative to a specific etch species and a second layer of electrically conductive metal (13) is formed on the first layer of electrically conductive metal having an etch rate relative to the specific etch species greater than the first layer and which preferably extends into the via. The first layer of electrically conductive interconnect is preferably aluminum, the first layer of electrically conductive metal is preferably a metal containing from about one percent by weight to about one hundred percent copper and the rest essentially aluminum and the second layer of electrically conductive metal is preferably copper doped aluminum having a lower copper content than the first electrically conductive layer.
87 Citations
38 Claims
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1. A method of fabricating an interconnect comprising the steps of:
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(a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via having a predetermined etch rate relative to a specific etch species; and (d) forming a second layer of electrically conductive metal on said first layer having an etch rate relative to said specific etch species greater than said first layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of fabricating an interconnect comprising the steps of:
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(a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) depositing a pure dopant layer on the walls of said via; (d) forming a second layer of copper or aluminum over said dopant layer which is more lightly doped than said doped layer or undoped; and (e) forming a third layer of one of doped copper or aluminum over said second layer. - View Dependent Claims (28)
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29. A method of fabricating an interconnect comprising the steps of:
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(a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via taken from the class consisting of copper for aluminum doping or tin or magnesium for copper doping; and (d) forming a second layer of electrically conductive metal on said first layer of doped or undoped copper or aluminum having a lower level of doping than said first layer. - View Dependent Claims (30)
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31. A method of fabricating an interconnect comprising the steps of:
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(a) providing a first layer of electrically conductive interconnect; (b) forming an aperture defined by walls and extending to said interconnect; (c) forming a barrier layer extending over said interconnect and said walls; and (d) forming one of a dopant layer or a doped layer of an electrically conductive metal over said barrier layer and within said aperture. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38)
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Specification