Method of preventing or suppressing sidewall buckling of mask structures used to etch feature sizes smaller than 50nm

摘要

We have discovered a method of preventing or suppressing the buckling of amorphous hard mask structures used to etch feature sizes smaller than about 50 nm. We have determined that buckling of the hard mask can be prevented by controlling the aspect ratio of mask features to be within a certain range when the features are sub 40-50 nm in size. In the case of amorphous hard mask structures, generally the aspect ratio of a feature should be controlled to be less than about 3 when the feature size is sub 40-50 nm in size; and, depending on the substrate to which the hard mask is adhered, the aspect ratio may need to be as low as about 1.0 or lower to ensure that there is no buckling of the hard mask sidewalls.