Image contrast slope and line edge roughness of chemically amplified resists for postoptical lithography

The reduction of line edge roughness (LER) or linewidth roughness is the most challenging issue associated with the development of resist processes for the next generation lithography. The extent of LER has been reported to correlate with the image contrast slope. Although the postoptical lithography such as electron beam and extreme ultraviolet lithographies can create high contrast images, low-energy electrons degrade image contrasts in these lithographies. The precise prediction of image contrasts requires the incorporation of the effects of low-energy electrons into process simulators. For the reduction of LER, better understanding of LER formation is needed. In this work, the authors proposed a simulation method for the calculation of latent images for postoptical lithographies on the basis of the sensitization mechanisms of chemically amplified resists.