Lawrence Berkeley National Laboratory

Advanced mask metrology tools play a key role in research and development towards future nodes of EUV lithography. Experimental studies are an essential complement to simulation data in photomask technology and lithographic imaging. We are commissioning a mask-imaging demonstrator powered by a high-brightness undulator light source at beamline twelve of the Advanced Light Source at Lawrence Berkeley National Laboratory. The instrument is a zoneplate-based actinic full-field EUV microscope similar to the SHARP microscope, enabling complementary imaging modes, increasing the photon flux at the mask by two orders of magnitude. At frame rates above one hundred hertz, more than a thousand individual pupil channels can be recorded per experiment site, resolving the source-angular spectrum produced by the illuminator. Arbitrary pupil fills can be synthesized from the image data. The data can be used to compute Fourier- Ptychographic reconstructions. Fourier Ptychography (FP) is a computational imaging technique that reconstructs the complex field of the object from a series of intensity images recorded under plane-wave illumination from different illumination angles. FP enables quantitative phase imaging. FP data can be used to emulate wafer-side through-focus behavior in anamorphic image data. We provide an overview of the instrument, discuss data acquisition modes, and present a range of image data, demonstrating short exposure times, FP, and source optimization.