SBIR Phase II: High Power Pulsed Fiber Laser for EUV Lithography

This Small Business Innovation Research Phase II project has the core objective to develop a modular, laser power scaling concept based on recent innovations in high efficiency fiber lasers. The proposed concept uses large mode area, chirally-coupled core fiber to construct high power, pulsed fiber laser modules that can be spectrally combined into a single, collinear beam delivering multi-kilowatts of average power. Power scaling of a laser source with characteristics appropriate for the generation of extreme ultraviolet (EUV) radiation is a key obstacle to the technical maturity of EUV lithography. EUV lithography is the leading candidate for high volume manufacturing of the next generation of semiconductor integrated circuits with critical dimensions of 22 nm or less. The Phase II effort builds on the successful Phase I feasibility and design results by developing the critical components and constructing a prototype laser module. Results expected from this work include construction and characterization of key laser components capable of withstanding high laser peak powers and demonstration of a breadboard, prototype fiber laser capable of producing pulse energy of 1 millijoule or more with pulse lengths of 5-30 nanoseconds at pulse repetition rates in the range of 50-200 kHz. The broader impact/commercial potential of this project is the continued advancement of semiconductor integrated circuit performance. A key metric in this advancement is the minimum critical dimension that can be realized in the manufacture of these devices. Advances in lithography have enabled a decrease of approximately 30% in this dimension every two years, which has led to a doubling every eighteen months in the number of transistors on an integrated circuit. This trend, known as Moore's Law, has fueled an explosion in the processing power, storage capacity, efficiency and affordability of microelectronic devices. EUV lithography, currently under development, is the critical manufacturing technology that is needed to sustain this trend on the five to ten year horizon. Development of a power scalable laser, operating in the nanosecond pulse regime, is a critical element in the practical realization of EUV lithography. Success in this endeavor will help to deliver continued advances in microelectronic devices that benefit fields of study and industry as diverse as genetic engineering, telecommunications, computer engineering and transportation.