Development of bottom antireflective coating for high-resolution KrF lithography

There are considerable interests in the application of KrF lithographic process to achieve the beyond 0.13 micrometers resolution pattern. Decreasing in KrF resist thickness for high resolution in the lithographic process needs improvements of Bottom Anti-Reflective Coating (BARC) physical properties such as high etch selectivity and low reflectivity in thin KrF BARC film (350 ~ 400 Angstroms). It is known that the real and imaginary refractive indices of BARC are changed by film density and absorbance. Our research group have studied two different chromophore classes (BM1 and BM2) of functional groups that are highly absorptive at 248 nm and achieve high etch selectivity. Also, we have evaluated the effects of polymer structure on BARC in terms of refractive index changes and film density.