Layout optimizations for double patterning lithography

Deep sub-wavelength lithography is one of the most fundamental challenges for future scaling beyond 32 nm as the industry is currently stuck at the 193 nm lithography. Many ingenious technologies/tricks are developed to push the limit of 193 nm lithography, e.g., immersion lithography and computational lithography. But they may not be sufficient for 22 nm patterning. Meanwhile, next-generation lithography, such as EUV (Extreme Ultra-Violet) lithography may not be available for mass production in the near future. As a practical solution, double patterning lithography (DPL) has become a leading candidate for 22 nm (and likely 16 nm) lithography process. DPL poses new challenges for overlay control, layout decomposition, and up-stream physical designs. In this paper, we will discuss some recent advancements and challenges in layout decompositions and DPL friendly layout optimizations.