Depositing tungsten into high aspect ratio features

摘要

Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials are provided. The method involves providing a partially fabricated semiconductor substrate and depositing a tungsten-containing layer on the substrate surface to partially fill one or more high aspect ratio features. The method continues with selective removal of a portion of the deposited layer such that more material is removed near the feature opening than inside the feature. In certain embodiments, removal may be performed at mass-transport limited conditions with less etchant available inside the feature than near its opening. Etchant species are activated before being introduced into the processing chamber and/or while inside the chamber. In specific embodiments, recombination of the activated species is substantially limited and/or controlled during removal, e.g., operation is performed at less than about 250° C. and/or less than about 5 Torr.

主权项

1. A method of filling a high aspect ratio feature provided on a partially manufactured semiconductor substrate, the feature having an opening and an interior, the method comprising:
introducing a tungsten-containing precursor and a reducing agent into a processing chamber; depositing a layer of a tungsten-containing material on the partially manufactured semiconductor substrate via a chemical vapor deposition reaction between the tungsten-containing precursor and the reducing agent, such that the layer partially fills the high aspect ratio feature; flowing an etching material into the processing chamber to contact the substrate; and selectively removing a portion of the deposited layer using the etching material at process conditions including a substrate temperature of less than about 250° C. and a pressure processing chamber pressure of less than 5 Torr such that more tungsten is removed near the feature opening than in the feature interior, wherein the etching material that contacts the substrate includes atomic fluorine and molecular fluorine, and wherein the amount of the deposited layer removed by atomic fluorine is at least ten times greater than the amount of the deposited layer that is removed by molecular fluorine.