摘要 |
When forming a trench in a porous low-K dielectric (such as an ILD) of a semiconductor device, a carbon-rich layer is formed in the sidewalls of the trench during trench etching. This carbon-rich layer may protect the trench from being excessively etched, which would otherwise form an undesirable hardmask undercut. The carbon-rich layer may be formed simultaneously with and during the etching process, by increasing the amount of carbon available to be absorbed by the ILD during the trench etching process. The existence of the extra available carbon may slow the etching of the carbon-enriched regions of the dielectric.
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