Electrolyte and process for electroplating copper onto a barrier layer
AssigneeAlchimer
InventorsVincent Mevellec, Dominique Suhr, Laurianne Religieux
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Abstract
The subject of the present invention is an electrolyte composition for depositing copper on semiconductor substrates covered with a barrier layer. This electrolyte contains the combination of imidazole and 2,2′-bipyridine, used as suppressor, and of thiodiglycolic acid, used as accelerator. The combination of these additives makes it possible to obtain a bottom-up filling on trenches of very small width, typically of less than 100 nm.
Claims25
An electrolyte suitable for filling trenches of a semiconductor substrate, said trenches having a width being less than 200 nm, the electrolyte having a pH higher than 6.7, and comprising:
- copper ions in a concentration between 0.4 and 40 mM;
- bipyridine in a concentration between 0.4 and 40 mM;
- imidazole in a concentration being between 1.2 and 120 mM;
- and
- thiodiglycolic acid in a concentration being between 1 and 500 mg/l,
- wherein the bipyridine concentration represents from 0.5 to 2 molar equivalent of the concentration of copper ions and the imidazole concentration represents from 1 to 5 molar equivalents of the concentration of copper ions.
Dependencies are inferred from the claim text.