摘要 |
The present invention provides PECVD methods for forming stable and hermetic ashable hard masks (AHMs). The methods involve depositing AHMs using dilute hydrocarbon precursor gas flows and/or high LFRF/HFRF ratios. In certain embodiments, the AHMs are transparent and have high etch selectivities. Single and dual layer hermetic AHM stacks are also provided. According to various embodiments, the dual layer stack includes an underlying AHM layer having tunable optical properties and a hermetic cap layer.
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