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Vivek M. Prabhu & Eric K. Lin, National Institute of Standards and Technology, Gaithersburg, USA

ABSTRACT

Advances in optical lithography, using chemically amplified photoresists, have continued to meet ITRS goals. However, lineedge roughness (LER) and critical dimension (CD) control remain technical challenges for upcoming 65nm and 45nm nodes because both the image resolution and the thickness of the imaging layer now approach the macromolecular dimensions characteristic of the polymers used in the photoresist film. With accompanying decreases in film thickness, the photoresist/ substrate and photoresist/air interfacial properties, and component distribution increasingly affect the overall performance of a photoresist. New measurement methods are needed to address fundamental issues that may limit the development of future photoresists.