This Small Business Innovation Research Phase I project will establish the feasibility of a power scalable, short pulse fiber laser that is suitable for use in Extreme UV Lithography (EUVL). A power scalable solution is proposed here, based on fiber lasers using Chirally-Coupled Core (3C) fiber that is 3X more energy efficient and dramatically more compact than competing alternatives. 3C fiber enables single-mode optical output from fibers with core diameters much larger than conventional double-clad fiber.
Successful completion of this project would provide a technology to extend photolithography for feature sizes below 22 nanometers. Currently available laser technology can deliver only one third of the power required for high volume manufacturing by EUVL. Source laser power scaling is a key enabler for high volume manufacturing with EUVL and hence the production of semiconductor integrated circuits (ICs) that are smaller, more powerful and more energy efficient.
The result of the Phase I research effort is the design for a fiber laser with average output power of 200 Watts, high optical beam-quality, and optical pulse duration of a few nanoseconds. The laser design features peak pulse optical power of 100 kilowatts or more. The target application for this laser is in semiconductor manufacturing. The overriding goal was to design a fiber laser for use as the basic building block in a power scalable, laser driven source of extreme ultraviolet (EUV) radiation required for next generation semiconductor lithography. The Phase IB effort focused on designing and fabricating a single-mode optical fiber with a central core size larger than 35-microns to enable scaling of the fiber laser to pulse energies greater than one millijoule. The design was enabled by taking advantage of a unique fiber structure known as Chirally-Coupled Core (3C) fiber. This effort resulted in a 40-micron core 3C fiber that demonstrated the feasibility of scaling the core size while maintaining a high quality output beam. The Phase II program proposes to develop a 200 Watt, short-pulse fiber laser prototype, suitable for installation at an external laboratory, for evaluation as a laser driver in an Extreme Ultraviolet (EUV) source. Current EUV lithography technology based on CO2 lasers has not delivered the power required for high volume manufacturing. Development of a power scalable laser, operating in the nanosecond pulse regime, is a critical element in the practical realization of EUV lithography, and is a key obstacle to its technical maturity. Successful development of the appropriate fiber laser modules and spectral combining technology can propel EUV lithography from demonstration phase to high-volume production. Development and commercialization of Extreme Ultraviolet (EUV) lithography processes are essential steps in scaling silicon based, nanoelectronics to the ultimate limits of CMOS technology. Current commercial lithographic processes have reached the technological limits of their capabilities. EUV technology is the only lithographic technique with the potential to achieve high volume production capability at critical dimensions of 22 nm or less, with acceptable economics within the next five years. Integrated circuits with diminishing critical dimensions have been the key to revolutionary advances in computer processing power, efficiency and device miniaturization over the past forty years. These advances in semiconductor performance have produced significant societal benefits in communications, healthcare, scientific research, safety, transportation and more. EUV lithography can enable the practical realization of entirely new generations of more powerful and efficient electronics for years to come. Commercialization of this technology and product concept will provide a basis for U.S. based manufacturing leadership in this critically important area of semiconductor manufacturing technology.
