Fabrication process for low resistivity tungsten layer with good adhesion to insulator layers
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsMing-Hsing Tsai, Sheng-Hsiung Cheu
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Abstract
A process for forming a low resistivity tungsten layer, for use as a metal gate structure, or a metal damascene structure, has been developed. The process features initial deposition of a metastable tungsten nitride layer, via a plasma enhanced, or metal organic chemical vapor deposition procedures, resulting in good adhesion, in addition to good step coverage, of the tungsten nitride layer, to underlying or adjacent insulator layers. The high resistivity, tungsten nitride layer is then converted to a lower resistivity tungsten layer, via a rapid thermal anneal procedure, performed in an argon ambient, or in vacuum.
Claims8
A method of forming a tungsten damascene structure, comprising the steps of:
- providing an opening in an overlying interlevel dielectric layer, exposing a top surface of a tungsten plug structure, located in a via hole in an underlying interlevel dielectric layer;
- depositing a tungsten nitride layer, completely filling said opening in said overlying interlevel dielectric layer;
- performing an anneal procedure to convert said tungsten nitride layer to a tungsten layer;
- and
- removing portions of said tungsten layer from the top surface of said overlying ILD layer, to create said tungsten damascene structure in said opening in said overlying ILD layer.
Dependencies are inferred from the claim text.