| 摘要 |
A method of etching multiple films with a dual layer hard mask wherein one layer is totally removed and the other layer partially removed during deep trench etching of the silicon substrate. In particular, a method of deep trench etching silicon substrates comprising the steps of providing a semiconductor substrate capable of being etched, with HBr/NF3/He/O2, having a layer of pad dielectric disposed depositing a layer of material capable of selective removability with respect to the pad dielectric, preferably BSG; depositing a layer of material having a slower etch rate than the semiconductor substrate and the layer of material capable of selective removability with respect to the pad dielectric, preferably, silicon oxide deposited by PECVD; patterning at least one of the layers, and etching the semiconductor substrate to form a trench and removing the layer of material having a slower etch rate than the semiconductor substrate, wherein trenches are of close proximity to each other.
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