Formation of metal silicide layer over copper interconnect for reliability enhancement
First Claim
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1. A method of forming an interconnect comprising:
- providing an interconnect dielectric layer on a substrate of a semiconductor structure, the interconnect dielectric layer having a top surface;
providing an interconnect opening in the interconnect dielectric layer;
forming an interconnect in the interconnect opening with the top surface of the interconnect dielectric layer exposed, the interconnect having an interconnect top surface below the top surface of the interconnect dielectric layer to form a recess in the interconnect opening;
treating the interconnect top surface, wherein the treating comprises forming an oxide layer on the interconnect top surface in the opening; and
after treating the interconnect top surface, forming a blanket metal silicide layer on the exposed top surface of the interconnect dielectric layer and filling the recess using a non-reactive process, wherein the non-reactive process improves interconnect reliability.
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Abstract
A method of fabrication of a sputtered metal silicide layer over a copper interconnect. We form a dielectric layer over a conductive layer. We form an interconnect opening in the dielectric layer. We form a copper layer at least filling the interconnect opening. We planarize the copper layer to form a copper interconnect in the interconnect opening. The copper interconnect is over polished to form a depression. We form metal silicide layer over the copper interconnect using a low temperature sputtering process. We can form a cap layer over the metal silicide layer.
24 Citations
29 Claims
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1. A method of forming an interconnect comprising:
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providing an interconnect dielectric layer on a substrate of a semiconductor structure, the interconnect dielectric layer having a top surface; providing an interconnect opening in the interconnect dielectric layer; forming an interconnect in the interconnect opening with the top surface of the interconnect dielectric layer exposed, the interconnect having an interconnect top surface below the top surface of the interconnect dielectric layer to form a recess in the interconnect opening; treating the interconnect top surface, wherein the treating comprises forming an oxide layer on the interconnect top surface in the opening; and after treating the interconnect top surface, forming a blanket metal silicide layer on the exposed top surface of the interconnect dielectric layer and filling the recess using a non-reactive process, wherein the non-reactive process improves interconnect reliability. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming an interconnect comprising:
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forming a dielectric layer on a substrate, the dielectric layer serves as an interlevel dielectric in which an interconnect is formed, the dielectric layer is prepared with an interconnect opening; depositing a conductive interconnect layer over the dielectric layer and at least filling the interconnect opening; polishing the substrate, wherein polishing removes excess conductive interconnect material to expose a top surface of the dielectric layer and recesses the interconnect material to form a recess in the interconnect opening such that a top surface of the interconnect material is below the top surface of the dielectric layer; treating a surface of the interconnect material by forming an oxide layer of the interconnect material on the top surface of the interconnect material in the interconnect opening; after treating the surface, forming a blanket metal silicide layer on the exposed top surface of the dielectric layer and filling the recess using a low temperature process with temperatures at about 180 degrees C. or lower, wherein avoiding the use of a high-temperature chemical reactive process improves interconnect reliability; and planarizing the metal silicide layer to expose the top surface of the dielectric layer and to form a metal silicide cap in the recess. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of forming an interconnect comprising:
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providing a substrate prepared with a dielectric layer in which an interconnect is formed; forming an interconnect opening in the dielectric layer, the interconnect opening comprising a dual damascene opening; forming a copper layer at least filling the interconnect opening, wherein the copper layer is formed by an electroplating or electroless process; planarizing the copper layer to expose a top surface of the dielectric layer and to form a copper interconnect in the interconnect opening, the copper interconnect having a top surface between about 100 and 300 angstroms below the top surface of the dielectric layer to form a recess in the interconnect opening; treating a surface of the copper interconnect which include forming a copper oxide layer on the surface of the copper interconnect in the interconnect opening, and performing a plasma treatment on the surface of the interconnect; after treating the surface of the interconnect, forming a metal silicide layer over the copper interconnect using a sputter process, wherein the metal silicide layer is formed using a sputter process at a temperature between about 20 and 180 degree C., the metal silicide layer is comprised of a material selected from the group consisting of WSi, CoSi, NiSi and CuSi, or a combination thereof; planarizing said metal silicide layer to expose the top surface of the dielectric layer and to form a metal silicide cap in the recess. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A method of forming an integrated circuit comprising:
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providing a substrate prepared with a dielectric layer in which an interconnect is formed, the dielectric layer is prepared with an opening, the dielectric layer having a top surface; filling the opening with a conductive layer, wherein the top surface of the dielectric layer is exposed and the conductive layer comprises a top surface below the top surface of the dielectric layer to form a recess in the opening; forming an interconnect cap in the recess with the top surface of the dielectric layer exposed, the interconnect cap is formed using a non-reactive process, wherein the non-reactive process improves interconnect reliability; and treating the top surface of the conductive layer prior to forming the interconnect cap, wherein the treating comprises, forming an oxide layer on the top surface of the conductive layer in the opening, and performing a plasma treatment on the top surface of the conductive layer. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification