H2-based plasma treatment to eliminate within-batch and batch-to-batch etch drift

Abstract

This invention relates to electronic device fabrication for making devices such as semiconductor wafers and resolves the detrimental fluorine loading effect on deposition in the reaction chamber of a HDP CVD apparatus used for forming dielectric layers in high aspect ratio, narrow width recessed features with a repeating dep/etch/dep process. The detrimental fluorine loading effect in the chamber on deposition uniformity is reduced and wafers are provided having less deposition thickness variations by employing the method using a passivation treatment and precoating of the chamber before substrates are processed. In a preferred process, after each wafer of a batch is finished, the passivation steps are repeated. In a further preferred process, after all the wafers of a batch are finished, the passivation and precoat procedure is repeated. A preferred passivation gas is a mixture of hydrogen and oxygen.