December 21, 2004 – Researchers at SEMATECH North have reached a milestone in reducing deposition tool-generated defects in mask blanks used for extreme ultraviolet lithography (EUVL). They have deposited EUV multilayers with as few as one defect/mask at 80nm resolution, which translates into 0.005 defects/square centimeter.

Technologists from SEMATECH, Veeco Instruments Inc., and Asahi Glass achieved an extremely low level of added defects in recent work with Veeco’s NEXUS system, an ion beam deposition (IBD) low defect density (LDD) tool for deposition of critical films.

Following a two-year effort to improve tool hardware, process parameters and handling protocols, the technologists deposited EUV multilayers with as few as one defect/mask at 80nm resolution, which translates into 0.005 defects/square centimeter. A state-of-the-art laser-based defect detection system was used to identify the defects.

“This is good news for the semiconductor industry, because mask blank defect reduction is a critical challenge for bringing EUVL technology into commercial fabs,” said David Krick, program manager for SEMATECH North’s Mask Blank Development Center (MBDC). “To put this achievement into perspective, imagine that a mask blank was expanded to the size of North Dakota. A single, 80 nm defect on that blank would be roughly the size of a basketball.”

Giang Dao, SEMATECH lithography director, called the milestone “technical payback” for the investment in SEMATECH North, a joint five-year program between SEMATECH and the University at Albany-State University of New York. SEMATECH North is located at Albany NanoTech, a global center for nanoelectronics research and development and home to the College of Nanoscale Science and Engineering at the University at Albany.

“Without the vision and support of New York’s public and academic leaders for SEMATECH North’s EUVL program, accomplishments such as this would not be possible,” Dao said.

For years, SEMATECH has led industry efforts to reduce defectivity in EUV mask blanks in order to have those devices available for commercial use before the end of the decade. The recent defectivity accomplishment is seen as an encouraging trend in the MBDC’s ultimate goal, which is to enable mask blank suppliers to develop processes that result in defect-free mask blanks, measured at 25nm resolution, by 2009.