Multiple Patterning Lithography

This chapter addresses general trends and examples of the evolution in advanced lithography methods beyond traditional single patterning technology. The ability to print multiple exposure passes to meet performance targets in a cost-effective manner has driven the search for the overall best techniques in multiple patterning. The need for continuous device scaling has significantly driven the development of new lithographic patterning techniques and imaging methods. The patterning technique chosen to print a given lithographic layer can have significant impact on the final design style, and vice versa. Considering all aspects and options to imaging approaches, layout decomposition, materials selection, integration scheme, and target performance in multiple patterning schemes, one can conclude that a significantly large number of possible forms of multiple patterning can exist. Integrated patterning essentially consists of forming feature edges by indirect methods. Multiple patterning beyond doubling can offer resolution improvement but at a cost of process complexity and control.