Consideration for application of NTD from OPC and simulation perspective

State of the art Extreme Ultra Violet Lithography (EUVL) gives high hope for further shrinkage of semiconductor devices, but currently, EUVL is not ready for 2xnm node manufacturing and ArF immersion must extend its capability in manufacturing 2xnm devices. Extending the limit of ArF requires varieties of Resolution Enhancement Techniques (RET) such as inverse lithography (ILT) , double patterning (DPT), spacer patterning and so on. One of the brightest candidate for extension of ArF for contact layer is negative tone development (NTD), since this process utilizes the high contrast of the inverse tone of the mask for patterning. NTD usually results in high process margin compared to conventional positive tone development (PTD) process1. Therefore, in this paper we will study application of NTD from optical proximity correction (OPC) and simulation perspective. We will first discuss difference of NTD from PTD. We will also discuss on how to optimize NTD process in simulation perspective, from source optimization to simulation calibration. We will also discuss what to look out for when converting PTD process to NTD process, including OPC models to design rule modification. Finally, we will demonstrate the superiority of NTD process through modeling and simulation results with considering these factors mentioned above.