Source Mask Optimization (SMO) <sup>1</sup> is proposed and being developed for the 32 nm generation and beyond in order to
extend dose / focus margin by simultaneous optimization of the illuminator source shape and a customized mask. For
several years now, mask optimization techniques have been improving. At the same time, the flexibility of the
illuminator must also be improved, leading to more complex illumination shapes. As a result, pupil fill is moving from a
parametric model defined by sigma value, ratio, clocking angle, subtended angle and/or, pole balance, to a freeform
condition with gray scale defined by light intensity in the illuminator. We have evaluated an intelligent illuminator in
order to meet requirements of SMO. Then we have confirmed controllability of the pupilgram.
Nikon's production immersion scanners, including the NSR-S609B and the NSR-S610C, have now been in the field for
over 2 years. With these tools, 55 nm NAND Flash processes became the first immersion production chips in the world,
and 45 nm NAND Flash process development and early production has begun. Several logic processes have also been
developed on these tools. This paper discusses the technical features of Nikon's immersion tools, and their results in
VLSI chips are becoming denser and the industry is now moving to the development of devices at the 65nm node. While Nikon is working toward the development of next-generation lithography tools, we are also making efforts to extend the life of DUV excimer steppers by continuing reductions in feature size without any major changes to the conventional process. Nikon's new model, the ArF Immersion Scanner NSR-S609B, utilizes immersion lithography in which the space between the projection lens and the wafer is filled with ultra pure water with a refractive index of 1.44. This immersion technology enables the NSR-S609B to break through the N.A. 1.0 barrier to achieve the world's highest N.A. of 1.07, an impossible feat by a conventional lithography or dry exposure. This system will contribute to the production of advanced 55nm and smaller devices. Latest evaluation results of the immersion imaging system and the new stage system are presented.