Method of improving mechanical properties of semiconductor interconnects with nanoparticles
First Claim
1. A method of forming a multi-layer structure comprising:
- forming one or more ultra low-k (ULK) dielectric layers with each alternating ULK dielectric layer having a plurality of metal filled trenches and vias formed therein,forming a cap, capping and sealing said ULK dielectric layers having said plurality of metal filled trenches and vias; and
spin capping nanoparticles forming a monolayer at an interface between said ULK dielectric layers and each of said caps.
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Abstract
In a BEOL process, UV radiation is used in a curing process of ultra low-k (ULK) dielectrics. This radiation penetrates through the ULK material and reaches the cap film underneath it. The interaction between the UV light and the film leads to a change the properties of the cap film. Of particular concern is the change in the stress state of the cap from compressive to tensile stress. This leads to a weaker dielectric-cap interface and mechanical failure of the ULK film. A layer of nanoparticles is inserted between the cap and the ULK film. The nanoparticles absorb the UV light before it can damage the cap film, thus maintaining the mechanical integrity of the ULK dielectric.
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Citations
14 Claims
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1. A method of forming a multi-layer structure comprising:
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forming one or more ultra low-k (ULK) dielectric layers with each alternating ULK dielectric layer having a plurality of metal filled trenches and vias formed therein, forming a cap, capping and sealing said ULK dielectric layers having said plurality of metal filled trenches and vias; and spin capping nanoparticles forming a monolayer at an interface between said ULK dielectric layers and each of said caps. - 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 multilevel Back-end-of-line (BEOL) stack, each level comprising:
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spinning a solution containing nanoparticles followed by drying out said solution; forming a ULK dielectric layer followed by UV cure; lithographic patterning lines or vias; transferring said patterned lines or vias into said ULK dielectric by etching; removing said nanoparticles at a bottom of open areas created by rinsing with organic solvents; surface cleaning by applying DHF and rinsing said solvents and said etching residuals; forming a liner made of TaN, Ta, W, WNx, TiNx, Ru, Co followed by Cu or Cu alloy deposition followed by electrochemical process of said Cu followed by annealing said Cu; and applying a chemical mechanical polish of said copper and liner overburden; and
depositing a SiCNH cap.
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Specification