Frits Zernike, Jr., 1931 – 2011

Lithography lost one of its own on July 12 with the death of Frits Zernike Jr. to Parkinson’s disease. Here is his obit from the New York Times:

Born and educated in Groningen, the Netherlands. A physicist with Perkin-Elmer Corp., Silicon Valley Group and Carl Zeiss, and first manager for Dept. of Energy’s Extreme Ultraviolet Lithography Program. Survived by his wife of 49 years, Barbara Backus Zernike, children Frits III, Harry, and Kate, daughter- and son-in-law Jennifer Wu and Jonathan Schwartz, and three grandchildren: Frits and Nicolaas Schwartz and Anders Zernike. Memorial service will be 3pm Thursday, July 28, at Essex Yacht Club, Novelty Lane, Essex, CT. Donations in his memory may be made to Dance for Parkinson’s, c/o NMS, 100 Audubon St, New Haven, CT 06510, or Community Music School, P.O. Box 387, Centerbrook, CT 06409.

Here is an excerpt from a post I made to this blog on February 27, 2009 concerning Frits:

“It was seven years ago that SPIE approached me with the idea of creating a major SPIE award in microlithography. I agreed to head up the effort, and gathered together a committee of other lithographers to establish the award process. Someone on the committee suggested naming the award after Frits Zernike, for three reasons. First, no major optical award had been named in his honor, even though the scientific contributions of this Nobel prize winner are legion. Second, the name has high recognition in the optical lithography community due to the ubiquitous use of the Zernike polynomial for describing lens aberrations. The third reason is more personal – Zernike’s son, Frits Zernike Jr., worked for many years in the field of lithography at Perkin-Elmer and later SVG Lithography before retiring. Some of us on the committee knew him, and when contacted he was very supportive of an award named for his father.”

Greetings From…

New Zealand was supposed to be the end of that sentence. But thanks a volcanic explosion in Chile, the answer has become Sydney, Australia. While we don’t yet know how long we’ll be stranded here (my family and I), we do know that all Qantas flights to NZ have been canceled for another day. So, now it’s a vacation in Australia for at least one more day!

By the way, what is bringing us to New Zealand is a two month teaching gig at the University of Canterbury in Christchurch, which begins in about a week.

For more details on our travails of travel, check out my wife’s blog on our New Zealand adventure:
http://smacknz.blogspot.com/

Litho in Las Vegas

The 3-beam conference here in Las Vegas began on Wednesday morning with the plenary session. Nick Economou discussed the history and current performance of the Helium Ion Microscope. What an amazing tool! It has much higher resolution than a scanning electron microscope (SEM) with far less charging. The result is truly amazing pictures of biological and other non-conducting samples. I can’t wait to see pictures of photoresist patterns with this tool – I’m sure it will quickly become indispensible, especially for line-edge roughness characterization.

Sam Sivakumar of Intel seems to be making a second career out of giving plenary talks (proof of the never-ending interest in hearing about what Intel is going to do next). His talk brought up a long-simmering (or at least recently-simmering) question that I have. Standard naming convention for semiconductor technology nodes cuts the name of the node in half for two generations out. Thus the 90-nm and the 65-nm nodes become the 45-nm and 32-nm nodes (sometimes rounding is necessary). Of course, these names have nothing to do with the dimensions of the features involved in the process, but the standard of dividing by two for the names has seemed inviolate. Today most state-of-the-art companies claim to be manufacturing at the 32-nm node. That means two nodes out would be the 16-nm node, right?

So I didn’t know what to think when Intel began calling it the 15-nm node. Why? Are they hoping for a 1-nm marketing advantage over their rivals? If they don’t get to the node first, will they say “Yes, but they are only doing 16-nm, but WE are doing 15”? A 1-nm advantage seems insufficiently significant, and now it seems that the marketing gurus at Intel agree. While the program listed Sam’s talk as having “15nm Node” in the title, his opening slide had changed the title to “14nm Node”. Now Intel will have a 2-nm advantage over the rest of us. That’s real progress.

Sam provided a couple of quotable moments in his talk: “Traditional scaling approaches will no longer work.” “Fundamental work is needed in LWR to affect improvement.” I agree.

Matt Malloy of SEMATECH gave an interesting talk on the sources of defects for nanoimprint lithography (of the Molecular Imprints step-and-flash variety). This is an important topic since defect density is the only serious roadblock to implementing nanoimprint in production. I was surprised to learn that the vast majority of defects come from the template manufacturing process. At least we know where to focus our attention now.

I was happy to hear from Dan Sanders of IBM Almaden Research that directed self assembly (DSA) has moved past the “trough of disillusionment” in the Hype Cycle and is now entering the “slope of enlightenment”. Progress on DSA in the last year has been remarkable, and I expect that progress to accelerate in the next year. This is a research area to get behind.

David Melville of IBM gave an invited talk on computational lithography. This quote was right on: “Effective optimization [of the total lithography process] is no longer in the realm of the lithography engineer.” Serious mathematicians and computational geeks are needed as well. What a different world from when I started computing lithography on my PC so many years ago.

A cool idea that I am still learning about is “Absorbance Modulation” materials. Essentially, they are like the old idea of contrast enhancement materials, but made erasable using a second wavelength of light (one that the underlying resist is not sensitive to). There are many variations on how such a material can be used to improve resolution, but the real goal would be to perform double patterning with just a double exposure process. Alas, no absorbance modulation materials are yet available at 193 nm.

On the last day of the conference I gave my paper – a work completed that morning and something completely different from what I had originally proposed in my abstract. That’s life on the (rough) edge of research.

The Mapper folks had a couple of talks promising a 1 wafer-per-hour maskless e-beam lithography tool by the middle of next year. If they succeed, that tool could be a game changer. I’ll be staying tuned, but the challenges remain great.

Finally, at the end of the day Alex Liddle of NIST had a fascinating talk on measuring acid blur in chemically amplified resists using single molecule fluorescence. Cool stuff, though more work is needed.

Another interesting 3-beams conference is over, and I can hardly wait for next year’s conference. I doesn’t hurt that it will be on the Big Island of Hawaii in 2012.

Aside: Thanks to Richard Blaikie for exposing me to this quote from Albert Einstein: “Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius – and a lot of courage – to move in the opposite direction.” This could be the motto of lithographers everywhere.

Litho in Las Vegas – Prologue

Las Vegas is not my favorite city. It is America’s monument to greed (and bad taste), where form not only wins over substance, it’s as if substance never even showed up for the race. This place relishes in its lack of roots, tearing down old facades to build newer, bigger facades (little is more pathetic than faded glitz) in an arms race of extravagance. It is all so purposely disorienting.

So why am I here? It is time for the 55th International Conference on Electron, Ion and Photon Beam Technology & Nanofabrication (EIPBN). That’s a mouthful, which is why attendees universally call it the triple-beam or three-beams conference. Fortunately, the conference is in a resort near the mountains outside of town. Still, even this place will not let you escape the Las Vegas vibes – you can’t get anywhere in the resort without walking through the smoke-filled Casino that fills its core. Ah well.

I don’t attend this conference every year, but I wish that I could. It is generally academic, with papers that are a shotgun blast of ideas ranging from cool to bizarre. I always come away inspired and with new things to think about and work on. That will be my way of judging success this year as well.

The conference will begin with a plenary session, but the festivities have already started with the traditional Tuesday evening welcome reception, this time including an Elvis impersonator. Welcome to Las Vegas.

Steven A. Orszag, 1943 – 2011

Dr. Steven A. Orszag, a renowned expert in computational fluid mechanics, died on May 1 at the age of 68. (His obituary in the New York Times can be accessed here.) One of his most important contributions was the development of spectral methods for solving complex fluid dynamics problems, greatly increasing the efficiency of the numerical calculations. These techniques are now standard in fluid dynamics, especially for turbulent flow, but are also used in a number of other applications of scientific computation.

It is one of those other topics that caused me to meet Steven. Dr. Orszag had a long collaboration with Dr. Eytan Barouch, of Clarkson and then Boston Universities. Eytan got involved in lithography simulation in the late 1980s (I worked with him quite a bit during those early years) and applied Orszag’s spectral methods to aerial image simulation problems. Eventually Barouch and Orszag formed Vector Technologies to market their lithography simulator FAIM. Orszag’s involvement was mostly advisory and on the technical side, so far as I could tell. In the 1990s Dr. Orszag was the coauthor of 16 SPIE proceedings papers on lithography simulation, and I met him a time or two at these conferences. Obviously bright and busy, it was clear to me that lithography was more of a hobby to Dr. Orszag, an interesting offshoot of his many scientific interests.

Steven Orszag also has a famous son – Peter Orszag, formerly the budget director for the Obama administration.

Celebrating Long Life

Yesterday I learned that my neighbor, Carroll McPherson, died. He was 101 and a half. When you are very young and very old, you get to count by half years. He died in his bed, surrounded by his family, in the home he has lived in since 1942. He was ready to die, at peace and waiting for death for the last year or so, though his body clung to the habit of life. I want to be like Carroll.

I’m sorry that I was not there to say the last goodbye, and to help his wife Martha and the rest of his family like our other neighbors did. I’m visiting my wife’s grandfather Ben in Washington to celebrate his 90th birthday. Like Carroll, Ben has lived a healthy and happy life, and just seems to keep on going. I want to be like Ben.

Tomorrow is the big birthday party, and when we are done toasting Ben, I’ll give a small toast to Carroll as well. The cycle of life can be beautiful even in death.

Still Room at the Bottom

Fifty years ago today, Russian cosmonaut Yuri Gagarin became the first human to leave Earth and enter space. (He was perfectly qualified for the job: he was short, and was willing to sit there and do nothing as he was hurled like a cannon ball into space.) If sputnik awoke the world to the technical possibilities of space, Gagarin awoke our sense of awe and adventure for space. I grew up in the sixties thinking that almost anything was possible, and that our future would be filled with bigger and better things. Flying into space implied that no barrier was too high to be surmounted by human ingenuity and effort.

But fifty years later the promise of space travel remains mostly promise. When I watched the 1968 film 2001: A Space Odyssey in 2001 (didn’t we all), I was struck by how little of our early vision for space exploration had actually come about. There is a simple lesson here that is very easy to forget: scaling up is hard. To build a building twice as tall requires more than twice as much steel and concrete. Launching twice the payload into space requires more than twice the rocket power. The scaling is superlinear, and that doesn’t make for good economics (or good physics). In our gravity-constrained world, bigger is sometimes better, but it is always much, much harder.

At the same time that most of us earthlings were swooning over the first manned space flight, a handful of engineers at Fairchild Semiconductor were working out the kinks on a much smaller project – connecting four transistors together on one slab of silicon to make the first commercial integrated circuit. Not too many people noticed this innovation at the time, let alone appreciated its significance. There would be no ticker-tape parades (though there would eventually be quite of few millionaires among this talented group, and even a few billionaires). But something important had begun, and the promise of the silicon IC revolution has exceeded all expectations.

(It’s interesting to note that much of the early work on integrated circuits was funded by the Apollo program in its desire to miniaturize electronics destined for space.)

And so another simple lesson is learned: scaling down doesn’t behave like scaling up. Not to say that making something smaller is necessarily easier, but smaller mean less – less material, less energy, less space. The scaling works in our favor. Of course, there are limits, and those limits become something close to insurmountable when the dimensions of the device reach atomic scales. But the room between the macroscopic dimensions of our everyday objects and the microscopic dimensions of the atomic scale is something like 6 or 8 orders of magnitude. As Richard Feynman famously said, there’s plenty of room at the bottom. Semiconductor technology has been steadily mining this room at the bottom, shrinking features from 25 microns to 25 nanometers in the last 50 years.

Is there still room at the bottom? I think so. CMOS transistors may only last for another factor of two of shrinking (or less), but other devices will allow dimensions closer to one or a handful of nanometers. And we have not yet begun to think of all the possible things we can make with a vast toolbox of micro- and nanofabrication technologies. (Alas, the phenomenal success of the CMOS transistor has probably crowded out a wide range of other useful devices.) So while the way we have scaled in the past (think Moore’s law) may not last, there is still plenty of room for innovation at the bottom. I suspect that my young children will one day marvel at the progress in scaling down during their lives, while wondering whatever happened to the promise of space travel.

History File – you can’t make this stuff up

Dead Sea Scrolls

A real ad that ran in the Wall Street Journal in 1954, by Mar Samuel (a vicar of the Syrian Orthodox Church), who personally owned four of the dead sea scrolls (he bought them from a shoe maker and antiquities dealer from Bethlehem named Kando). Thanks to this ad, they were bought by the Hebrew University, through an intermediary; they already owned three scrolls. I have not heard how much they paid.

BTW, the dead sea scrolls were uncovered in various caves between 1948 and 1954 in (then) Jordanian-controlled parts of the West Bank. Their importance were not widely recognized until the mid 1950s, after Edmund Willson published his 1955 book “The Scrolls from the Dead Sea”.

Musings of a Gentleman Scientist