A comprehensive approach for micro and multiple bridges mitigation in immersion photolithography

Efforts to extend 193 nm lithography have introduced multiple patterning solutions to print a single level layer. Due to this increased complexity, defectivity on each layer is becoming very critical. Micro and multiple line bridges are one of the primary challenges in photolithography contributing to this complexity. These defects originate from several root causes and are difficult to eliminate. Point-of-use filtration plays a significant role on the mitigation of such defects. The impact of filtration rate and pressure was previously documented. In this research, we demonstrate that the combination of membrane and pore size selection, photoresist optimization, and hardware optimization can impact micro and multiple bridge mitigation in a 45 nm line/space pattern created through immersion lithography.