SEMATECH reaches milestone in defect cleaning for EUV mask blanks

April 12, 2007 — /BUSINESS WIRE/ — ALBANY, NY –Technologists at SEMATECH have successfully detected and cleaned 10 nm particles from mask blanks for use in extreme ultraviolet (EUV)lithography—pushing the technology another significant step toward readiness for advanced manufacturing.

The technical achievement was reported at SEMATECH’s Mask Blank Development Center (MBDC), one of several major R&D facilities within Albany’s College of Nanoscale Science and Engineering (CNSE). Process tools from Lasertec Corp. of Japan and Hamatech of Germany proved essential to the milestone.

“SEMATECH believes that the success of EUV depends on our ability to detect and remove particles as small as 10 nm, which is at the extreme limit of our inspection capability,” said Abbas Rastegar, Senior Member Technical Staff at the MBDC. “Our findings indicate that this degree of precision will be necessary for EUV to be successfully implemented for the 22 nm technology generation.”

Putting the challenge in perspective, Rastegar explained that a 10 nm particle is so miniscule that 100,000 of them could line up on the head of a pin. However, such small particles become significant at the 22 nm half-pitch technology generation if they appear in the wrong places on an EUV mask, which contains comparably tiny patterns that are used to define the circuits and devices in microchips.

Currently, the Lasertec M7360—jointly developed by SEMATECH—is the most sensitive defect inspection equipment for mask blanks, with detection capability for particles 30 nm in diameter. Using a combination of the Lasertec M7360 and an atomic force microscope (AFM), MBDC engineers were able to locate, mark and measure 10 nm silicon particles intentionally deposited on a quartz mask blank. Subsequent cleaning of the mask blank with SEMATECH’s advanced cleaning processes, which included the use of Hamatech’s ASC5500 tool, removed all of the targeted particles, as confirmed by AFM.

In efforts reported earlier, the MBDC successfully removed all particles of 30 nm and greater from an EUV mask substrate. However, demonstrating that a single 10 nm defect can be removed is an important scientific achievement, highlighting the importance of defect shape in cleaning at these small dimensions, according to Michael Lercel, SEMATECH’s Lithography Director. He noted that higher-resolution defect-inspection tools, combined with highly efficient cleaning techniques, are still needed to ensure EUV mask blank process maturity—which is a continuing focus of the MBDC.

Since early 2005, SEMATECH has achieved the world’s best results in EUV mask blank cleaning. Early this year, MBDC scientists succeeded in removing all particles of 30 nm and greater from the “quality area” of an EUV mask blank.

For 20 years, SEMATECH® ( has set global direction, enabled flexible collaboration, and bridged strategic R&D to manufacturing. Today, we continue accelerating the next technology revolution with our nanoelectronics and emerging technology partners.

Dan McGowan
[email protected]


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