Bottom Antireflection Coating-Resist Interactions

When the footing has an optical origin, it is related to a phase jump of the reflected light at the interface between the BARC and the resist. The magnitude of the phase angle change depends on the film s optical constants and its thickness. The phase jump can result in a standing wave at the resist-BARC interface. A resist 

Dammel, Anti-reflection coatings theory and practice, SPIE Short Course No. SCI 18 (2005). 

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Figure 9.11 Bottom antireflection coating-resist interactions on different substrates BARC, Si OyN, TiN. (After R. Dammel...

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