Integrated process for sputter deposition of a conductive barrier layer, especially an alloy of ruthenium and tantalum, underlying copper or copper alloy seed layer
First Claim
1. A method of forming a liner structure for a copper metallization, comprising:
- providing a substrate having a hole formed in a dielectric layer;
a first step of forming a first barrier layer over at least sidewalls of the hole comprising an alloy of at least 5 at % of a refractory metal chosen from Groups IVB, VB, and VIB of the periodic table and at least 5 at % of a platinum-group metal chosen from Group VIIIB of the periodic table except iron; and
a second step of forming a copper seed layer over the adhesion layer which does not fill the hole.
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Accused Products
Abstract
A fabrication method and a product for the deposition of a conductive barrier or other liner layer in a vertical electrical interconnect structure. One embodiment includes within a a hole through a dielectric layer a barrier layer of RuTaN, an adhesion layer of RuTa, and a copper seed layer forming a liner for electroplating of copper. The ruthenium content is preferably greater than 50 at % and more preferably at least 80 at % but less than 95 at %. The barrier and adhesion layers may both be sputter deposited. Other platinum-group elements substitute for the ruthenium and other refractory metals substitute for the tantalum. Aluminum alloying into RuTa when annealed presents a moisture barrier. Copper contacts include different alloying fractions of RuTa to shift the work function to the doping type.
148 Citations
29 Claims
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1. A method of forming a liner structure for a copper metallization, comprising:
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providing a substrate having a hole formed in a dielectric layer;
a first step of forming a first barrier layer over at least sidewalls of the hole comprising an alloy of at least 5 at % of a refractory metal chosen from Groups IVB, VB, and VIB of the periodic table and at least 5 at % of a platinum-group metal chosen from Group VIIIB of the periodic table except iron; and
a second step of forming a copper seed layer over the adhesion layer which does not fill the hole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of forming a liner structure for a copper metallization, comprising:
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providing a substrate having a hole formed in a dielectric layer;
a first step of forming a first layer over at least sidewalls of the hole comprising tantalum and between 80 and 95 at % ruthenium. - View Dependent Claims (15, 16, 17, 18)
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19. A metallization structure, comprising:
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a dielectric layer formed over a substrate and including a hole over a conductive feature in the substrate;
a first layer comprising tantalum and between 80 and 95 at % ruthenium formed on at least sidewalls of the hole. - View Dependent Claims (20, 21, 22)
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23. A metallization structure, comprising:
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a dielectric layer formed over a substrate and including a hole over a conductive feature in the substrate;
a first layer formed on at least sidewalls of the hole and comprising an alloy of at least 5 at % of a refractory metal chosen from Groups IVB, VB, and VIB of the periodic table and aat least 5 at % of a platinum-group metal chosen from Group VIIIB of the periodic table except iron; and
a copper layer formed over the first layer within but not filling the hole. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification