Two Pioneers Recognized for Contributions to Lithography

Obert Wood, pioneer in EUVL

Obert R. Wood is a principal member of the technical staff in the Strategic Lithography Technology Department at GLOBALFOUNDRIES. He was on the technical staff at Bell Laboratories for 34 years and has extensive experience in extreme-ultraviolet lithography (EUVL), ultrahigh intensity lasers, and laser surgery. He will receive the Frits Zernike Award for his pioneering contributions to EUV lithography, from conception to the threshold of high-volume manufacturing.

"If someone were to ask me to name one person who has contributed more than anyone to EUVL, I would respond without any doubt that Obert Wood is that person," says SPIE Fellow Bruno La Fontaine, Senior Director at ASML. "He has made immense contributions to EUVL."

La Fontaine notes Wood's pioneering work in the late 1980s when he built one of the first lithography systems using multilayer coated EUV mirrors, which led to the first high-quality images of sub-100-nm features in resist. This put EUVL (a.k.a. soft x-ray lithography at the time) solidly in the list of front contenders to succeed optical lithography.

During the 1990s and the early 2000s, Wood expanded his trailblazing research, publishing papers on multilayer mirrors, optical designs, optical testing, optics lifetime, aberrations and focus testing, sources, resists, masks, and metrology.

As fully integrated systems were becoming available during the late 2000s, Wood proved that EUV lithography could be successfully integrated into normal semiconductor processing to produce working SRAM devices. This was a formidable advance toward the acceptance of EUV as the main technology to follow immersion lithography.

In a series of SPIE presentations, Wood has detailed the EUV process integration and its insertion strategy from the 32-nm down to the 14-nm nodes, some of the most detailed revelations published. Today, he continues to work on EUV lithography at GLOBALFOUNDRIES in preparation for the technology's pending implementation in high-volume manufacturing.

Read Wood's papers and watch his presentations on the SPIE Digital Library: spie.org/O-Wood

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Akiyoshi Suzuki's contributions both broad and deep

The Frits Zernike Award will also be presented to Akiyoshi Suzuki in recognition of his innovations on all phases of lithography exposure tools, including proximity printing, projection steppers, projection scanners, 1X and reduction types, reflective and refractive types, g-line, I-line, 248 nm, 193 nm, and 13.5 nm.

During his 40-year career at Canon, Suzuki's contributions in microlithography, starting from contact to early projection systems, were pivotal. His early work on two-mirror wafer lithography systems, along with later two-mirror designs for flat-panel display lithography, have made an impressive impact on both the semiconductor and display industries. In 2014, Suzuki joined Gigaphoton as a technical advisor.

"Akiyoshi's portfolio of contributions is exceptionally broad and deep," says SPIE Fellow Andrew R. Neureuther of University of California, Berkeley. "This includes pioneering work on alignment, precision stages, immersion, ArF, F2, and double exposure. His nearly 100 U.S. patents and well over 100 Japanese patents, which are almost all in the field of microlithography, attest to this."

Neureuther adds that throughout Suzuki's long career, he repeatedly made technology-extending contributions to proximity printing, i-line, DUV, and even EUV. "His solutions were practical and often leveraged his mathematical modeling of the physics of lithography," says Neureuther.

Of particular note are the use of multiple wavelengths to reduce standing wave effects in contact printing, the use of 2:1 mirror radii to minimize aberrations in two-mirror systems, and the use of off-axis quadrapole to selectively enhance the printing of Manhattan geometries. When quadrapole illumination became available, there was a nearly two-fold increase in the depth-of-focus of resist materials. Resist chemists initially attributed depth-of-focus increase to their new polymers only to realize later that the increase was mainly associated with the new off-axis illumination.

"In several of these cases," says Neureuther, "Suzuki's insight came from his careful understanding of mathematical modeling, thus showing an unusual capacity to leverage the combination of theory and practice."

Read Suzuki's papers on the SPIE Digital Library: spie.org/Suzuki

Related Article:

History of the SPIE Frits Zernike Award
The Frits Zernike Award for Microlithography was created to honor significant contributions to the field of optical lithography.