Densification and reduction of lithographic features sizes keeping low defectivity is one of the biggest challenges in the patterning area. In order to extend 193 immersion capabilities and meet advanced applications needs, multi exposure image mode is a promising option for non-high volume manufacturing. It allows from a unique pattern with a fixed critical dimension (CD) and pitch, to obtain more dense patterns in a large surface without any process loop of standard flow, a huge benefit compared to litho-etch-litho-etch (LELE) approach. The study carried out explores this method with a specific design of pillars array printed using Negative Tone Development (NTD). The multi-image option relies on exposing multiple times the same initial pattern with a low image-to-image overlay. Based on intrinsic scanner performances, imageto-image placement error should be less than two nm. In this paper, many functionalities are explored to customize patterns from a single and unique mask design. One stake is to transfer (into silicon) a 2 mm * 2 mm pillar array design with a pitch divided by two, covering a wide surface on a 300 mm wafer and answering overlay and stitching requirements. Final results give well defined pillars which intra-wafer CD uniformity (3σ) satisfies application process requests. By using a flexible multi-image mode, mask constraints (cost and quality) can be relaxed, i.e. with a larger pitch structure on the reticle than the targeted one, final feature can be achieved. This development can be extended to hybrid lithography such as NanoImprint Lithography (NIL) or specific applications such as optics.
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