The image placement remains an important aspect of photomask metrology. Not only the position accuracy of features for an individual mask – representing one layer in a complete chip design – have to meet stringent requirements. The complete mask set for all layers have to match in order to get a functional device.
With the introduction of multi-pattering schemes most difficult layers in terms of critical dimensions have to be split into separate layouts and overlayed with each other. These tasks require registration metrology tools which employ high resolution capabilities and yet unprecedented specifications on reproducibility and accuracy for precise image placement measurements.
PROVE® neXT offers proven best in class repeatability and accuracy for mask manufacturing as well as Multibeam and VSB calibration. It works with a litho-grade 193nm optics for lowest aberrations. The system offers a better resolution than any other optical registration measurement tool with an NA of 0.8 for the measurement of smallest production features. All types of photo and nano–imprint masks can be precisely measured without loss of image contrast. A fast throughput can be realized for all measurement tasks including local registration map (LRM).
The FAVOR® platform enables productivity and reliability enhancement through intelligent automation.
Local Registration Map (LRM)
It is a new measurement mode for PROVE® that allows to measure registration in a macroscopic field instead of tiny features. This will be especially helpful to calibrate mask writers.