SEMATECH Advances Infrastructure for Extreme Ultraviolet Lithography (EUVL)

SEMATECH engineers have made significant advances in moving forward the infrastructure that will prepare extreme ultraviolet lithography (EUVL) for cost-effective manufacturing, according to papers being presented here at the 2007 International EUVL Symposium.

An outstanding set of SEMATECH-led technical achievements and breakthroughs in EUVL are featured in nine papers from SEMATECH authors and seven partner papers involving lithographers from the global consortium. The research leading to these accomplishments took place at SEMATECH’s facilities at the College of Nanoscale Science and Engineering (CNSE) in Albany, NY, and demonstrates the consortium’s commitment to deliver cost-effective manufacturing solutions to its member companies and the semiconductor industry.

“SEMATECH continues to produce results that chip-makers need to show that EUVL is manufacturable,” said Michael Lercel, Lithography director. “Here at the EUVL Symposium, we’re showing practical results for mask blank defect reduction, more efficient optical system designs, effective reticle handling, and other areas that help drive cost, which is emphasized in our cost-of-ownership models.”

“The significant advances made by SEMATECH researchers and engineers working at the UAlbany NanoCollege demonstrate SEMATECH’s leadership in spurring next-generation advances in nanoelectronics, which is enhanced by its growing presence and partnership at CNSE’s Albany NanoTech,” said Dr. James G. Ryan, professor of nanoscience and associate vice president of technology at CNSE. “This represents another important step forward in the development and commercialization of EUVL technology, which is seen as vital to the future of nanoelectronics manufacturing.”

Following is a sampling of advances revealed by SEMATECH technologists in papers being delivered at the symposium:

• The best EUV mask blank defect density in the world today – 0.1 per cm2 at 56 nm resolution – will be reported by Chan-Uk Jeon, program manager of the Mask Blank Development Center in Albany, NY. SEMATECH also has created a detailed database of the source of the defects and is developing mitigation methods, such as smoothing, to reduce pit defects. (This SEMATECH smoothing process has achieved an 800X improvement in defect levels.) SEMATECH’s work likely will enable mask blanks to be ready for EUV beta tools in 2009.
• SEMATECH has achieved only five added defects at 56 nm sensitivity in EUV mask blank defect totals, according to a paper by Patrick Kearney, Member Technical Staff. This milestone was enabled with industry-leading 56 nm defect inspection sensitivity on multilayer coated blanks, and is rooted in SEMATECH’s strategy of collaborating with suppliers to bring together all elements of the industry.
• A manufacturable EUVL reticle solution also requires defect-free reticle handling. EUVL reticle protection using SEMATECH’s “sPod” design shows an average of less than one particle added per 100 separate reticle transfers, as explained in a paper by Long He, project engineer. Tests also show the sPod as a potential solution for shipping and storage.
• Using the industry’s best EUV resist exposure capability, SEMATECH has demonstrated that effective resolution down to 24 nm can be achieved with current resists and optimized illumination conditions. These results are documented by Andy Ma, EUV resist bench project manager. Ma also describes remaining resist challenges, including linewidth roughness and photospeed.
• Current optical designs for EUV collectors are not very efficient, but SEMATECH has developed a series of upgrades that could boost collector efficiency by 2.8X. That would reduce the industry’s critical dependence on high-power sources or improve tool throughput and cost-effectiveness. The designs are explained in a paper by Michael Goldstein, Senior Technologist.
• Detailed cost-of-ownership targets for EUVL – as determined by SEMATECH’s detailed cost models – will be reported by Phil Seidel, Senior Member Technical Staff. These performance targets have been integrated into the consortium’s technology development projects, and show that the key elements for cost-effective EUVL include source power, optics lifetime, and mask blank defect reduction.

“SEMATECH continues to move beyond theory and alpha concepts to deliver manufacturable EUV solutions for our member companies and the industry,” Lercel said. “We are leading EUV mask blank development with the world’s best defect inspection and characterization capability and multilayer deposition capability, and leading-edge imaging capability for EUV photoresists.”