Method of copper barrier layer formation
First Claim
1. A method of copper diffusion barrier formation comprising:
- providing a dielectric layer having an opening to copper metal interconnect wiring;
depositing a diffusion barrier layer over the dielectric layer covering and lining the opening;
doping with silicon the surface of the diffusion barrier layer by a silane plasma treatment to form silated silicon doped compounds on the surface of the diffusion barrier layer;
annealing thermally at high temperature the surface of the silicon doped diffusion barrier layer to drive in the silated silicon doped compounds into the diffusion barrier layer and to form a highly dense, amorphous silicon doped diffusion barrier layer.
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Abstract
A process in the fabrication of integrated circuits has been developed for copper diffusion barrier layer. This invention teaches a method of barrier formation by the deposition by physical vapor deposition (PVD) sputtering (reactive sputtering for nitride compounds) or chemical vapor deposition (CVD) of a copper metal diffusion barrier layer, which consists of the following materials: TaN, Ta, TiN, or WN. Next in the process, is the plasma silation and silicon doping of the barrier layer material followed by high temperature thermal annealing. Scanning electron microscope (SEM) analysis of the silated barrier materials show amorphous films with clusters of silicide material with low silicon concentration and high film density (>99%). Low diffusion properties (amorphous films lack grains for fast grain boundary diffusion) and good chemical vapor deposited (CVD) copper seed layer adhesion, are found with the both TiSiN and TaSiN barrier layers made by this method. The current invention applies to lining both a single and dual damascene structure to form copper metal barrier layers and adhesive copper seed layer for interconnects and vias prior to electrochemical deposition (ECD) of copper.
57 Citations
30 Claims
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1. A method of copper diffusion barrier formation comprising:
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providing a dielectric layer having an opening to copper metal interconnect wiring;
depositing a diffusion barrier layer over the dielectric layer covering and lining the opening;
doping with silicon the surface of the diffusion barrier layer by a silane plasma treatment to form silated silicon doped compounds on the surface of the diffusion barrier layer;
annealing thermally at high temperature the surface of the silicon doped diffusion barrier layer to drive in the silated silicon doped compounds into the diffusion barrier layer and to form a highly dense, amorphous silicon doped diffusion barrier layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for fabricating a copper diffusion barrier layer comprising:
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providing a dielectric layer having an opening to copper metal interconnect wiring;
depositing a diffusion barrier layer over the dielectric layer covering and lining the opening;
doping with silicon the surface of the diffusion barrier layer by a silane plasma treatment to form silated silicon doped compounds on the surface of the diffusion barrier layer;
annealing thermally at high temperature the surface of the silicon doped diffusion barrier layer to drive in the silated silicon doped compounds into the diffusion barrier layer and to form a highly dense, amorphous silicon doped diffusion barrier layer;
depositing a copper seed layer over the silicon doped diffusion barrier layer;
thus, forming robust defect-free copper diffusion barrier layer and copper seed layer for subsequent electrochemical deposition of plated copper upon the copper seed layer and chem-mech polishing back of excess copper to form inlaid copper interconnects. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for fabricating MOSFET and CMOS devices on a silicon semiconductor substrate with damascene structures using electrochemical deposition of copper and chemical vapor deposition of copper seed layer on a silicon doped diffusion barrier layer comprising:
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providing a semiconductor substrate having an insulating layer deposited upon said substrate;
providing a level of copper metal interconnect wiring patterned within an insulating layer over said insulating layer;
providing a dielectric layer having an opening to the copper metal interconnect wiring;
depositing a diffusion barrier layer over the dielectric layer covering and lining the opening, with the diffusion barrier layer material selected from the group consisting of TaN, Ta, TiN and WN;
doping with silicon the surface of the diffusion barrier layer by a silane plasma treatment to form silated silicon doped compounds on the surface of the diffusion barrier layer;
annealing thermally at high temperature the surface of the silicon doped diffusion barrier layer to drive in the silated silicon doped compounds into the diffusion barrier layer and to form a highly dense, amorphous silicon doped diffusion barrier layer;
depositing a copper seed layer over the silicon doped diffusion barrier layer;
depositing by electrochemical deposition copper conducting material over the copper seed layer and removing the excess material layers by chemical mechanical polish to form conducting copper interconnects and contact vias, which are inlaid structures. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification