Study on Approaches for Improvement of EUV-resist Sensitivity

摘要

Several methods to improve sensitivity of EUV resist, with a couple of key points of acid generation efficiency and de-protection reaction efficiency. Larger loading of PAG to increase the secondary electron absorption possibility, cation unit design to lower the lowest unoccupied molecular orbital of cation, and lowering ionization potential of polymer to enable efficient secondary electron generation, were discussed in the viewpoint of acid generation efficiency. Larger size of anion structure design on PAG was applied to special formulation of small loading of quencher to minimize necessary generated acid concentration to give enough de-protection reaction amount, and to higher PEB temperature resist process to maximize de-protection reaction efficiency.