interferometry and optical metrology • EUV lithography • materials properties • coherence • synchrotron and advanced short-wavelength optics • image processing • experiment control • photomask research • microscopy • extreme ultraviolet • extreme ultraviolet
LIGHT is the most ubiquitous and extraordinary phenomena in all of science. It flows toward us from glowing screens and from the farthest knowable reaches of space and time ago. No matter the wavelength, no matter the color, light is light. It’s elegant path through the universe can be described by the simplest equations and the most complex interactions. Penetrating X-rays, the warmth of the Sun, and the familiar AM radio crackle all share the shades and glimpses of the same underlying physics.
Light carries energy in discrete wave-like packages called photons—quintillions of them arrive in a single blink. Photons are enigmatic yet highly predictable, arriving on our eyes, our cameras, and our detectors in a steady stream or a soft, slow rain. Scientists exploring light employ mathematics, experiments, and analysis to incrementally deepen our understanding. Our work gives rise to greater predictive abilities which we use to create fantastic new tools and techniques for science.
As a scientist working with light, every day is a new gift: time to think and learn; time to build and do; time to test and measure and troubleshoot and rebuild and test again; time to grow and refine and improve over time; and ultimately, time to collaborate and share and pass on, so that others can build upon the work we do, and surpass us.
Since 1993, my research at Lawrence Berkeley National Laboratory’s (LBNL) Center for X-Ray Optics (CXRO) has been dedicated to short-wavelength extreme ultraviolet (EUV) and soft x-ray light. This light cannot be seen by the naked eye, yet it is so strongly reactive that it cannot propagate a millimeter through the air before becoming extinguished. That extreme reactivity makes possible fantastic probes of material and chemical properties, while the short-wavelength enables us to squeeze it down to create nanometer-scale imaging resolutions and surface-probing interferometers with sub-Å (<10-10 m) sensitivity.
All of the conventional elements associated with visible-light optics (lenses, mirrors, prisms, etc.) have to be re-envisioned, re-engineered, and re-designed for highly specialized applications at short wavelength. That is what I do. I work to create and explore new capabilities and applications of short wavelength light, to bring techniques from other wavelength ranges to the EUV for the first time, and to develop unique tools and instruments at the forefront of my field.
I lead an exceptional team of researchers who have created and now operate a one-of-a-kind extreme-ultraviolet microscope called SHARP, a research tool dedicated to improving commercial chip-making technologies. My team and I study aspects of advanced photolithography, the central process used in the mass-production of computer chips. I also collaborate with several teams on the development of interferometric wavefront metrology to create short-wavelength optics, beamlines, mirrors, lenses, and imaging systems capable of performing at the physical limit of nanoscale resolution.
Our work is made possible by a talented, dedicated team of engineers and technicians whom we routinely challenge to expand the realm of what’s experimentally possible. These projects have been funded by industry and government agencies who recognize that millions of dollars spent on research can create billions of dollars in real economic activity. Those agencies, and numerous program managers and directors within them, are visionary leaders who have repeatedly fought to foster and nurture our work. They deserve profound credit for their essential role in our success and our accomplishments.
Prior to my work on SHARP, I led the SEMATECH Berkeley Actinic Inspection Tool (AIT). I worked to create and interferometrically align the SEMATECH Berkeley Microfield Exposure Tool (MET) and two prior four-mirror EUV optical systems that were part of the Engineering Test Stand (ETS) project for the EUV LLC. I tested and aligned six different EUV Schwarzschild objectives in a series of early EUV optics demonstration experiments. As part of a Lab-funded R&D program, I developed interferometric techniques for the alignment and testing of glancing-incidence Kirkpatrick-Baez mirror pairs used on soft x-ray beamlines. I have also conducted numerous studies on Fresnel zone plate lenses.
I served for four years on the ALS Users Executive Committee, with one year as Chairman. I have been section head of EUV Lithography for the annual EIPBN meeting, and on the program committee for the X-Ray Optics and Metrology section of the SPIE Annual Meeting. I am a co-chair of the upcoming IWXM 2015— International Workshop on X-Ray Optics and Metrology, and co-chair of the SPIE Advanced Lithography 2016—Extreme Ultraviolet (EUV) Lithography conference.
Kenneth A. Goldberg
Deputy Director, Center for X-Ray Optics
Materials Sciences Division
Lawrence Berkeley National Laboratory