Electrolyte concentration control system for high rate electroplating

摘要

An electroplating apparatus for filling recessed features on a semiconductor substrate includes an electrolyte concentrator configured for concentrating an electrolyte having Cu2+ ions to form a concentrated electrolyte solution that would have been supersaturated at 20° C. The electrolyte is maintained at a temperature that is higher than 20° C., such as at least at about 40° C. The apparatus further includes a concentrated electrolyte reservoir and a plating cell, where the plating cell is configured for electroplating with concentrated electrolyte at a temperature of at least about 40° C. Electroplating with electrolytes having Cu2+ concentration of at least about 60 g/L at temperatures of at least about 40° C. results in very fast copper deposition rates, and is particularly well-suited for filling large, high aspect ratio features, such as through-silicon vias.

主权项

1. An electroplating apparatus for depositing copper on a semiconductor substrate having one or more recessed features, the apparatus comprising:
(a) an electrolyte concentrator module configured for concentrating an electrolyte comprising a dissolved copper salt by removing water from the electrolyte using water evaporation, the electrolyte concentrator module comprising an inlet port configured for receiving a non-concentrated electrolyte from a source of non-concentrated electrolyte, an outlet port configured for delivering warm concentrated electrolyte to a concentrated electrolyte reservoir, a dry air port configured for introducing dry air, a wet air port configured for removing wet air containing evaporated water, and a heater configured for maintaining the electrolyte in the concentrator module at a temperature of at least about 40° C.; (b) the concentrated electrolyte reservoir in fluidic communication with the concentrator module, wherein the reservoir is configured for receiving the warm concentrated electrolyte from the concentrator module and for delivering the warm concentrated electrolyte to an electroplating cell; (c) the electroplating cell in fluidic communication with the concentrated electrolyte reservoir, wherein the electroplating cell is configured for receiving the warm concentrated electrolyte from the concentrated electrolyte reservoir, and for bringing the warm concentrated electrolyte in contact with the semiconductor substrate at the electrolyte temperature of at least about 40° C. ; and (d) a controller comprising program instructions for
(i) providing dry air to the electrolyte concentrator module through dry air port; and(ii) concentrating the electrolyte in the concentrated electrolyte would have formed a precipitate at 20 ° C.