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Method for enhancing W fill process

IP.com Disclosure Number: IPCOM000238819D
Publication Date: 2014-Sep-19
Document File: 2 page(s) / 164K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for enhancing the Tungsten (W) fill process by eliminating the nucleation delay for Tungsten growth and providing a smooth W surface through an additional surface treatment step.

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Method for enhancing W fill process

Keyholes and hollow metal defects are severe yield detractors in the contact module for 22, 14nm, and beyond. There is not simple solution other than relaxing the ground rules.

A Fill Tungsten (W) process, which involves a deposition-etch-deposition (dep-etch-dep) sequence, can mitigate the problem. This methodology includes a Nitrogen Triflouride (NF3) etch chemistry that leaves nitrogen and fluorine residues. The residues cause a nucleation delay and surface roughness, which compromise the benefit of the dep-etch-dep process.

Figure 1: Fill W process

A method is proposed to eliminate the nucleation delay for Tungsten growth and to provide a smooth W surface. After the dep-etch steps, the method incorporates a surface treatment step, which can be either a Silane Soak or a Diborane Soak for thirty seconds to two minutes. The third step or dep2 can proceed without nucleation delay to improve the gap fill quality.

Figure 2: Surface treatment step

Figure 3: Silane/Diborane Soak after EFx Etch

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