Last week Hiroshi Ito, co-inventor of the chemically amplified resist (along with C. Grant Willson and Jean Fréchet), passed away after a long illness. Dr. Ito was working as a post-doc under Grant Willson at IBM when they developed the concept and the first example of a chemically amplified photoresist in 1980, now the dominant technology for semiconductor manufacturing. Dr. Ito became an IBM fellow in 2008.

Unfortunately, a personal commitment forced me to leave San Jose Thursday morning, and so I have missed what is usually one of the better days of talks and posters. Since I have nothing to report on Day 4, I’ll instead talk for a bit about the Zernike Award.

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. In 2004 the first Frits Zernike Award for Microlithography was given to Burn Lin. After three years I stepped down as chair of the committee.

I’m the 6th Zernike Award winner. Which got me thinking – just which aberration is the 6th Zernike? A quick check (I looked it up in my textbook!) showed that it was 3rd order x-coma. So I decided that each Zernike winner should be named after the corresponding Zernike polynomial term. Here are the results:

Z1: Burn Lin – x-tilt
Z2: Grant Willson – y-tilt
Z3: Tim Brunner – defocus
Z4: David Williamson – astigmatism
Z5: Martin van den Brink – 45 degree astigmatism
Z6: Chris Mack – x-coma

So, if you aren’t already in a coma from 4+ days at the SPIE Advanced Lithography Symposium, it is time to start thinking about who should become Z7: y-coma.

Midweek in the conference the adrenaline of the first few days begins to wear off. Combine that with a few nights in a row with less sleep than desired and all of a sudden sitting through six papers in a row starts to seem like work. I focused on all things LER on Wednesday, trying to find the Resist Conference papers that weren’t so packed with chicken-wire diagrams and 100-letter chemical names that mere mortals might be able to understand them. I think I’m making the same comment as last year: I’m amazed at how slow our progress is at understanding the fundamental mechanisms of line-edge roughness. There is a good chance that LER will be the ultimate limiter of lithographic resolution – why isn’t the industry putting more effort into the science of it?

In the Optical Lithography session, John Petersen’s talk on interference lithography (a topic I have worked on in the past) was well received. I agree with Bruce Smith’s comment: this technology has been too long neglected.

In the evening I skipped the DfM or MfD or f-in MD or whatever it was called panel and went straight for the hospitality suites (which were more plentiful than the previous night). The Hitachi party included a routine by the stand-up comedian Don McMillan (the power-point comedian and former chip designer). He was extremely funny, as always, and the sake was excellent. Thanks to Hitachi for being such a good host.

On Tuesday, the Optical Lithography conference begins, and with four of the five conferences going in parallel things are in full swing. Still, every time I walk into one of the cavernous meeting rooms that last year would have been standing room only and this year is more than half empty, I’m reminded of the difference that one year can make.

I began by sneaking into the Alternative Lithography conference (hoping no one would recognize me) to get on update on ASML’s EUV program. I found out that the throughput of the alpha-demo tool (of automotive junkyard fame) had been improved to 4 wafers per hour. But lest you become too excited about that speedy feat, the maximum throughput for a week was 100 wafers. When I talked a user of the tool, however, he said that last week was in fact a very good week: 42 wafers processed. But then, no one defined what was meant by a wafer. Because the flare on the tool is so bad, you have to separate the exposure fields by many millimeters to keep each field from influencing its neighbors. Thus, a “wafer” has on the order of 10 exposure fields (sometimes less) – several factors of two less than a product wafer. So how far off is the throughput of the alpha-demo tool compared to the beta tool spec?

I spent most of the day in the Optical Lithography conference. The highlights of the day were the keynote by Bruce Smith (he always gives a good talk) and the Chris Bencher paper on “gridded design rules”: how to scale SRAMs, and possibly logic, for another three or four generations using sidewall-spacer double patterning. After seeing that presentation I have become a fan of the sidewall-spacer approach – I think it will take us a long way.

My biggest complaint of the day was about session organization. After an entire session of talks by IBM on source-mask optimization, I was tired of the topic and IBM’s take on it. The Applied Materials session wasn’t as monotone (and wasn’t as long) but still was too much of one company. The conference organizers (you know who you are!) need to prevent such one-company sessions.

Tuesday night is usually a time for hospitality suite overload. Not this year. This pickings were sparse and they were soon picked over by hungry (and cheap) lithographers. I ended up spending most of the night at Gordon Biersch.

The first day of the conference was an exciting one for me. I was honored and humbled to become the 6th winner of the Frits Zernike Award for Microlithography. I’ll have more to say about this later, but there is no doubt that this moment was one of the highlights of my career.

The plenary talks were exceptional this year, especially the last two. Here are some of my favorite phrases and quotes:

Lisa Su, Freescale: “Lithography-induced complexity”

Gilad Almogy, Applied Materials: “2009 will likely be the worst year ever for our industry.”

Bernie Meyerson, IBM: “Where have all the GHz gone?”
“Atoms don’t scale.”
“Scaling is dead. Moore’s Law isn’t.”
The Albany EUV alpha-demo tool “looks like you rolled an electromagnet through an automotive junkyard.”

When the conference sessions began, I attended the resist conference. It was great to witness the presentation of the first Jeff Byers Best Poster Award. I am extremely gratified to see Jeff’s memory honored in this way, though I’m sure Jeff would have shook his head in disbelief at the mere thought of such a thing! Thanks to the resist conference organizers for creating this wonderful award. At the end of the first session, just before lunch, Cliff Henderson inserted into his talk a 70th birthday recognition for Grant Willson, including beautiful collage picture of Grant and ending with a rousingly off-key rendition of the Happy Birthday song. Congratulations Grant! It’s fun to see you embarrassed.

The afternoon papers did not generate much excitement for me, and I guess I am so used to it now that I didn’t even get riled up when I saw the graphs with no numbers on the axes or the study that compared “material A” to “material B” and found, amazingly, that material A was better.

In the evening, I stood by my two posters for two and a half hours – tiring but fun. The good thing about the low attendance is that the poster session was actually manageable this year – the crowds were not so great and one could easily navigate through the isles and see the posters. Not that I did. The disadvantage of giving a poster is that you don’t get to see any of the others. Still, I had many great discussions with people who came by.

The day ended with dinner (and beer) at Gordon Biersch. A day in heaven for a lithographer.

It’s that time of year again – time to be back in San Jose for the 33rd annual SPIE Advanced Lithography Symposium. Looking back, I realize that this is the 25th consecutive Advanced Lithography (formerly Microlithography) Symposium that I have been to. That’s a lot of years! The conference has sure changed since those early days, most spectacularly in the growth of papers and attendees. In that sense, this year’s conference is harking back to a bygone era – attendance is expected to be down more than 50% from last year (due mostly to company travel restrictions). I suppose, though, that it is not fair to make such a comparison, since the number of papers is down only slightly from last year (barring an unexpected jump in the number of cancelations). It will still be impossible to see every presentation and poster that I would like!

The earliest indicator of a slow year came today, Sunday, during the short courses. Five courses were canceled and the rest had very low attendance numbers – my course drew 11 students, down from my average of 20 – 30. Still, it was a good group of students and teaching my “world according to NILS” class was fun as always.

The outlook for our industry is bleak, and yet I’m selfishly excited about this year’s symposium. I’ve been working on a fundamental understanding of line edge roughness, creating a complete stochastic model for lithography. I’ve made a lot of progress lately and I’m really looking forward to my two poster papers Monday night – some of my best work ever, I think. Let the conference begin!

The past ten years have been hard on the magazine publishing industry, with 2008 a particularly bad year. No one’s quite sure how web-based publishing will affect print in the end, but there have already been many casualties. Last month one of my favorite trade publications, Microlithography World, bit the paper-shredding dust. MLW was the brain-child of Sid Marshall, the editor of Solid State Technology (a magazine founded by his father, Sam Marshall) until that magazine’s purchase by PennWell. First published in January, 1992, MLW was thin and ran quarterly, but it filled a void in the publishing world, which previously didn’t offer a dedicated space for lithography publications.

As the magazine was launched, Sid contacted me about publishing a paper in this new quarterly. Instead, I proposed a more radical idea: I would write a short tutorial paper for every edition of the magazine. Sid agreed, and in January, 1993 the first “Lithography Tutor” article appeared. Here is the introduction I wrote for that first article:

“Welcome to The Lithography Tutor, a new regular feature of Microlithography World. As the name implies, the purpose of this column is to present lithography information in a tutorial format. Each issue of Microlithography World will carry a two to three page edition of this continuing series on the basic principles of optical lithography. To give you a brief outline of what is to come in the next several issues, we’ll begin by studying optics. How is an image formed by a projection optical system (stepper or scanner)? What is the influence of wavelength, numerical aperture, coherence, illumination? Then, we will examine how this image propagates through the photoresist (including absorption and standing waves) and exposes the resist. Finally, the properties of development will be discussed. From here, we can begin discussing lithography as a system, define what is meant by lithographic quality, and look for ways to optimize our lithography system to maximize its quality. All this in two to three pages per issue! I’m not sure how long it will take to get through all of these topics, but I’ll certainly have fun writing this column. I hope you will enjoy reading it.”

And I did have fun writing my column. I looked forward to it each quarter, since it forced me to figure out not just how to present information, but how to explain it. It was also a great pleasure working with the editor who took over for Sid, Marc Levenson (a.k.a. “M. David”).

In the spring of 1996 the column was renamed The Lithography Expert – it seems the publisher liked the idea of having an expert write its articles rather than a mere tutor (I guess that means I was promoted, though my pay remained the same: nothing). When the last MLW came out in November 2008, I had written a total of 63 Tutor/Expert articles – quite a run! Much of the information and explanations found in those articles made it into my textbook, Fundamental Principles of Optical Lithography, so that even as MLW disappears, the spirit of the Lithography Tutor/Expert lives on. Still, I’ll miss the deadline pressure to find another interesting lithography topic amenable to a good 2-page explanation. Maybe I’ll have to write another book to fill that need in me to explain.

At the beginning of this year, IEEE Spectrum asked me to write an article about double patterning for the general electrical engineering audience. Sounding like fun, I agreed. The editor then warned me to think about the process as a “collaborative” writing experience with the editors of the magazine. That has certainly proven to be true, since the final article bears little resemblance to the first draft I submitted in May. Still, the result, I think, serves the basic purpose of explaining to a general technical reader what is going on in advanced lithography and why.

The article is entitled “Seeing Double” and appeared in the November issue of IEEE Spectrum.

Grant Willson, friend and fellow professor at the University of Texas at Austin, has won just about every award that the chemistry profession has to offer. And since his work straddles the fence between science and engineering, he’s won just about every award that the chemical engineering profession has to offer as well. Add to that his accolades while at IBM and the respect of the lithography community (winning the Frits Zernike award, its highest honor), and it would be fair to say that his accomplishments have received some well-deserved recognition.

Last month, though, Grant’s recognition rose to a new level. He was one of eight recipients of the 2007 National Medal of Technology and Innovation, our nation’s highest honor for technological achievement. In October he was presented his award by President Bush in a White House ceremony.

His wife Debbie sneaked a video recording of the presentation on her digital camera. Grant shakes the President’s hand and then tells him a joke, getting him to laugh. Then after the reading of the citation [“for creating lithographic imaging materials and techniques that have enabled the manufacture of smaller, faster and more efficient micro-electronic components”] he and Bush both pose doing the “hook ‘em horns” hand gesture. Awesome.

Congratulations, Grant.

Early this year, SPIE (the optical engineering professional society) asked me to write an article for their magazine devoted to careers in optics, SPIE Professional. They wanted to hear any advise I might have for people in, or thinking about entering, the field of semiconductor lithography.

I thought for a moment and then asked, “Are you sure you really want my honest opinion?” They assured me that they did, and so I wrote a short article giving my unfiltered opinion as to whether a career in lithography was a good idea. When I submitted it, I asked again, “Are you sure you want to publish this?” To their credit, SPIE wanted only my true views, with no spin or sugar coating. The article has just come out. SPIE members can access it at http://spie.org/x4274.xml (the article is called Fab Future). The print version should be in the mail soon, if it hasn’t been sent already.

Here is the tag line for the article:

The “Litho Guru” takes a dim view of lithography remaining a top dog in semiconductor manufacturing and in fueling Moore’s Law. Growth and fun are slowing.

It’s not really an upbeat assessment of the potential for a career in lithography, or the semiconductor industry in general. But then, for those of us working in that field, this is not news.