Enabling cost effective patterning by addressing the origins of resist stochastics

To enable cost effective patterning of future nodes, solutions need to be found which avoid strong increases of the exposure dose, whilst simultaneously meeting the patterning fidelity requirements. We report on our latest understanding of the origin of local variations, as these dictate the exposure dose, and we recommend how to work towards lowering the local variations without substantially increasing dose. In particular we propose to directly address the significant non-photon driven pattern variability, as this may be more effective in reducing the pattern variability than current resist/process optimization. We also discuss how, based on theoretical modeling, a resist with a graded absorption coefficient could assist in reducing pattern variability while keeping stochastic defectivity and dose under control.