| abstract |
A method is provided for removing sidelobes that are formed when patterning a positive photoresist layer with an Att. PSM, Alt. PSM or a binary mask with scattering bars. A water soluble negative tone photoresist is coated over the positive photoresist pattern and is exposed through a mask having small islands that correspond in shape, size and location to the small holes in the mask used to pattern the positive tone photoresist. After development, exposed negative tone photoresist covers sidelobes formed by the positive tone process. The negative tone photoresist functions as a mask for a subsequent etch transfer of the positive tone pattern into the substrate. A method of aligning openings in a positive tone pattern over the same openings in a negative tone pattern is also useful in preventing sidelobes in the positive tone photoresist from being transferred into the substrate. |