Mask Bias optimization for NTD lithography process

NTD (Negative Tone Development) lithography process is widely used in the manufacture of the advanced technology. Because the NTD solution behavior is different from PTD (Positive Tone Development), the NTD photo resist has better litho-capability than PTD for certain kinds of lithography features such as trench and hole patterns. It is more difficult to both setup the NTD process and develop NTD photo resist than PTD process. To make lithography process and photoresist meeting the requirement for NTD process, Mask Bias for an anchor point is one of important factors.In this paper, we will report that by using different Mask Bias of anchor point, the NTD process with a certain photoresist can be optimized to meet the lithography process requirement and get better process performance.