| abstract |
Method and apparatus for cleaning a substrate having a plurality of high-aspect ratio openings are disclosed. A substrate can be provided in a plasma processing chamber, where the substrate includes the plurality of high-aspect ratio openings, the plurality of high-aspect ratio openings are defined by vertical structures having alternating layers of oxide and nitride or alternating layers of oxide and polysilicon. The substrate can include a silicon oxide layer over a damaged or amorphous silicon layer in the high-aspect ratio openings. To remove the silicon oxide layer, a bias power can be applied in the plasma processing chamber at a low pressure, and a fluorine-based species can be used to etch the silicon oxide layer. To remove the underlying damaged or amorphous silicon layer, a source power and a bias power can be applied in the plasma processing chamber, and a hydrogen-based species can be used to etch the damaged or amorphous silicon layer. |