Self-Aligned Double and Quadruple Patterning Layout Principle

Self-Aligned Double Patterning (SADP) has become one of the most promising processes for 20nm node technology and beyond. Despite its robustness against overlay, it is a challenging process for designers since predicting the wafer image instantly is almost impossible. Self-Aligned Quadruple Patterning (SAQP) is also critical technology for sub-10nm process but more complex than SADP, so it is too difficult to design a layout intuitively. Needless to say designing layout by applying N times sidewalls intuitively is impossible for almost everyone. In this paper, we clarify a new intuitive principle for SADP layout. The principle uses "Base patterns" painted in different two colors interchangeably. The proposed method enables us to design SADP layout simply by connecting and cutting fundamental pattern arbitrarily with a few restrictions. Another benefit is that either of two colors in the pattern can be used as mandrel. We can apply the principle to not only SAQP but also N times sidewall processes. Considering these advantages, layout formed by sidewall process becomes designer-friendly.