Extreme ultraviolet lithography (EUVL) is well on its way to commercialization, but several critical issues must be addressed to keep the technology on track, leading professionals were told recently at the second International EUVL Symposium in Antwerp.
More than 350 lithography experts representing approximately 80 companies were shown evidence of technical progress in all EUV areas, including advancements in high power sources, defect-free mask reticles, and high numerical aperture (NA) reflective optical systems.
Also, advancements in EUV mask blank development and resist testing were outlined by International SEMATECH (ISMT), while updates were provided on Japan's efforts in developing radiation sources, optics and exposure tools.
"It was very encouraging to see more than 350 scientists gathered here in Antwerp as clear proof of the activity around the world on EUV Lithography," said Rob Hartman, general chair of the symposium and chairman of the European EUV Cluster Steering Council. "Forty-two percent of the 354 participants came from Europe, as might be expected from the location, while about 100 joined from Asia and more than 100 came from the United States." Hartman added, "We recognize a strong drive for developing EUV technology, but would like to see more firm commercial commitments from semiconductor companies."
The three-day gathering, held September 30-October 2, was organized by ASML and Interuniversity MicroElectronics Center (IMEC), in conjunction with ISMT, Micro-Electronics for European Applications (MEDEA+), and Japan's Association of Super-advanced Electronics Technology (ASET). At the conclusion, the Symposium Steering Group identified six critical issues facing the industry over the next few years:
- Source output power and lifetime, including condenser optics lifetime
- Availability of defect-free masks
- Reticle protection during storage, handling and use
- Projection and illuminator optics lifetime
- Resist resolution, sensitivity and line width reduction (LWR)
- Optics quality for the 32 nm node
Luc Van den hove,VP Si Technology IMEC and co-chair of the symposium, remarked: "In Europe alone, some 80 companies, institutes and universities are working on EUVL, not only in the frame of MEDEA+ but also starting in the sixth framework program of the European Commission. Through our strategic relationship with ASML, we intend to install one of the first full-field exposure tools in our newly built 300 mm facility."
Chuck Gwyn, who was recognized by the Steering Group for his efforts to have EUVL technology identified as next generation lithography in the International Technology Roadmap for Semiconductors (ITRS), noted: "Technical progress was demonstrated in all areas, including advancements in high power sources, defect free mask reticles, and high-NA reflective optical systems. These achievements, along with the expanded industrial participation by the 82 companies represented at the symposium and workshops, are focusing on implementation of EUVL in high-volume manufacturing before the end of the decade."
Kevin Kemp, EUVL program manager at ISMT, stated: "EUV development activities in the U.S. continue to increase in scope and depth, and progress is being made in all key areas. The ISMT-North program in Albany, New York, is up and running, and the first tools in the Mask Blank Development Center have been installed and qualified. Technology transfer between researchers and industry is also accelerating, and we are starting to see significant improvements in the quality of blanks from commercial suppliers."
An assessment of Japan's activities was offered by Shinji Okazaki, regional chair for the Symposium and director of ASET's EUV Process Technology Research Department: "The Japanese government is also promoting a source development program through MEXT [Ministry of education and science technology]," he said. "In April, the metrology program moved from ASET to the EUVA consortium. Nikon and Canon are collaborating to develop pre-competitive areas of optics and exposure tool development at EUVA. ASET is continuing its efforts in the development of mask and resist technology."