C-Quad polarized illumination for back end thin wire: Moving beyond annular illumination regime

The objective of this work is to describe the advances in the use of C-Quad polarized illumination for densest pitches in back end of line thin wire in 32m technology and outlook for 28 nm technology with NA of 1.35 on a 193nm wavelength scanner. Through simulation and experiments, we found that moving from Annular to C-Quad illumination provides improvement in intensity and contrast. We studied the patterning performance of C-Quad illumination for ID dense, semi dense, isolated features with and without polarization. Polarization shows great improvement in contrast and line edge roughness for dense pattern. Patterning performance of isolated and semi-isolated features was the same with and without polarization. ©2009 SPIE.