Tungsten filling method

Abstract

This invention discloses a method for filling tungsten. The method includes: providing a substrate placed in a reaction chamber, the substrate comprising a dielectric layer having a plurality of horizontally extending recessed structures; introducing a first reactive gas into the reaction chamber, the first reactive gas comprising a hydrogen-containing gas adsorbed onto the inner wall surface of the recessed structures; introducing a second reactive gas and an auxiliary gas into the reaction chamber, the second reactive gas comprising a tungsten-containing precursor, and the auxiliary gas comprising at least nitrogen gas; the tungsten-containing precursor reacts with the hydrogen-containing gas adsorbed on the inner wall surface of the recessed structures to grow tungsten; wherein the first reactive gas, the second reactive gas, and the auxiliary gas are pumped into the reaction chamber by a pressurized method. By introducing nitrogen gas into the auxiliary gas, this invention can significantly reduce the fluorine content and resistivity of the deposited tungsten layer, improving device performance and reliability.

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