Gapfill of variable aspect ratio features with a composite PEALD and PECVD method

Abstract

The invention relates to gapfill of variable aspect ratio features with a composite PEALD and PECVD method, and specifically provides methods and apparatus for filling one or more gaps on a semiconductor substrate. The disclosed embodiments are especially useful for forming seam-free, void-free fill in both narrow and wide features. The methods may be performed without any intervening etching operations to achieve a single step deposition. In various implementations, a first operation is performed using a novel PEALD fill mechanism to fill narrow gaps and line wide gaps. A second operation may be performed using PECVD methods to continue filling the wide gaps.

Description

technical field [0001] The present invention relates to the field of semiconductor processing, and more particularly to gap filling of variable aspect ratio features using hybrid PEALD and PECVD methods. Background technique [0002] The fabrication of integrated circuits involves many and varied steps. One frequently employed operation is to deposit a dielectric film in the gaps between features patterned on or in the substrate. One purpose of depositing this material is to form a void-free, seam-free fill in the gap. As device sizes get smaller in the context of DRAM, Flash and logic, for example, it becomes increasingly difficult to achieve this type of ideal fill. [0003] Although deposition methods such as high density plasma (HDP), sub-atmospheric chemical vapor deposition (SACVD) and low pressure chemical vapor deposition (LPCVD) have been used for gap filling, these methods cannot achieve ideal filling performance. Flowable chemical vapor deposition and spin-on-d...

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Problems solved by technology

[0004] An additional challenge is to simultaneously fill gaps of different sizes on the substrate

For example, a deposition method optimized for wide gaps with small aspect ratios may not be suitable for filling narrow gaps with high aspect ratios, and vice versa

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