Multilayer reflective optics have enabled photolithography machines that can print most advanced semiconductor structures using Extreme UV wavelengths. While the technique is now used for high volume chip production in industry, researchers already work on potential upgrades using even shorter wavelengths. Target is 6.7 nm, about half the 13.5 nm value currently employed, which would reduce the smallest dimensions of the chip pattern.
At the latest International EUVL Source Workshop, held 4-6 November in Amsterdam, Dr. Andrey Yakshin from the Industrial Focus Group XUV Optics (University of Twente) could report a record reflectivity of 66.5% for 6.7 nm at normal incidence. This value is close to the current 13.5 nm reflectivity value, and an important achievement for enabling next generations of the successful lithography process. This result places the Twente group again at the top of the world’s thin film physics research groups!