Experimental procedure acid diffusion measurement

Photochemically generated acid must diffuse in resist film to catalyze desired reactions and to provide a gain mechanism for amplification. However, excessive diffusion (into the unexposed areas) destroys the linewidth control and eventually the resolution. Thus, as the minimum feature size becomes smaller and smaller, the control of acid diffusion plays a more important and difficult role. Therefore, investigation of acid diffusion in chemical amplification resist film is one of the most active areas of research today. A number of experimental procedures to measure acid diffusion length have been reported [67-88] ... 

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