Optimization of resolution enhancement technique at 45nm node

Different Resolution Enhancement Technologies (RET) were studied at 45 nm node. To meet the requirementof45 nm node, patterns of different pitches were analyzed and compared for selecting the best choice for 45 nm node lithography. Traditional Off-Axis Illumination (OAI) and new illumination were used for comparison together with different mask types (alternating PSM, attenuating PSM and binary mask). The printability of their combination using the immersion tools was considered. Also, for hyper NA imaging, polarization effect was taken into consideration for analysis. By optimizing the illumination and combined with PSM, the new OAI named double arc together with Y-polarization had obviously improvement for DOF. Finally, Double Bottom Anti Reflectivity Coating (DBARC) was used and their thicknesses were optimized, reduced the swing curve effect, and improved the image fidelity through the resist.