Latest performance of immersion scanner S620D with the Streamlign platform for the double patterning generation

Abstract

Currently, it is considered that one of the most favorable options for the 32 nm HP node is pitch-splitting double patterning, which requires the lithography tool to achieve high productivity and high overlay accuracy simultaneously. In the previous work [1] , we described the concepts and the technical features of Nikon's immersion scanner based on our newly developed platform, Streamlign, designed for 2nm overlay, 200wph throughput, and short setup time. In this paper, we present the latest actual performance of S620D with the Streamlign platform.Owing to the high repeatability of our new encoder metrology system, Bird's Eye Control, and Stream Alignment, S620D achieves less than 2 nm overlay accuracy, less than 15nm focus accuracy, and successful 32 and 22 nm L/S pitchsplitting double patterning exposures. Furthermore, the results at high scanning speed up to 700 mm/s are fine and we have successfully demonstrated over 4,000 wpd throughput, which confirms the potential for high productivity. Nikon has developed this Streamlign as an optimized long life platform based on the upgradable Modular 2 structure for upcoming generations. The performance of S620D indicates the possibility of immersion extension down through the 22 nm HP node and beyond.

Stability and calibration of overlay and focus control for a double patterning immersion scanner

“…In the case of the NSR-S620D, it has a hybrid metrology system consisting of encoders and interferometers, not only used for XY control, but also for Z measurement [5] . Therefore, we can continuously monitor the position of the stage using both encoders and interferometers for optimal positioning control, without any additional metrology requirements or throughput loss.…”

Signal Processing Using Karhunen–Loève Expansion for Wafer Focus Measurement in Lithography

“…To respond to this shrinkage requirement, semiconductor exposure tools, such as steppers and scanners that have a high numerical aperture (NA) and projection optics for a shorter exposure wavelength, have continuously been developed. [1][2][3] Since NA is high, the depth of focus (DOF) on a wafer is several hundred nanometer or less under the present condition, therefore several ten nanometer focus control, approximately 10% of DOF, is required in lithography. However, the accuracy of the focus measurement of the actual process wafer does not meet current requirement value.…”