摘要 |
A method for etching a high aspect ratio feature through a mask into a layer to be etched over a substrate is provided. The substrate is placed in a process chamber, which is able to provide RF power at a first frequency, a second frequency different than the first frequency, and a third frequency different than the first and second frequency. An etchant gas is provided to the process chamber. A first etch step is provided, where the first frequency, the second frequency, and the third frequency are at power settings for the first etch step. A second etch step is provided, where the first frequency, the second frequency, and the third frequency are at a different power setting.
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