Patterning performance of hyper NA immersion lithography for 32nm node logic process

We have developed the lithography process for 32nm node logic devices under the 1.35NA single-exposure conditions. In low-k1 generation, we have to consider the minimum pitch resolution and two-dimensional pattern fidelity at the same time. Although strong RET (Resonance Enhancement Technique) can achieve the high image contrast, it has negative effects like line end shortening and resist pattern collapse. Moderate RET such as annular illumination can combine the minimum pitch resolution and two-dimensional pattern fidelity with hyper NA illumination condition. The simulation and experimental results indicate that the minimum pitches should be determined as 100nm for line pattern and 110nm for contact hole pattern, respectively. The isolated contact hole needs SRAF and focus drift exposure to improve DOF. Embedded SRAM cell of 0.125&mgr;m2 area is clearly resolved across exposure and focus window.