This week, SEMATECH (along with Imec and SELETE) is sponsoring back-to-back symposia on EUV lithography and extensions to immersion lithography in Prague, Czech Republic. Since I was invited to speak at the immersion symposium, and because I love Prague, I decided to attend.

I have to begin with a story of personal transformation. Five years ago I had to have extra pages sewn into my passport because every page was full of stamps. (I won’t even tell you how many millions of miles I have flown in my life – too many.) I like traveling, especially to new locations, but even for me that amount of travel was too much. But in preparing for this trip, I glanced at my passport as I was making my travel arrangements and noticed that it had been expired for nine months! That shows how much my life has changed (much for the better) since I became a gentleman scientist (and a father) four years ago. Life is good.

I’m now here in Prague, jet-lagged and listening to EUV papers (not a happy combination). I’ll report on my impressions of the EUV conference tomorrow.

Day 3 is the last day of the conference this year. Due to significantly lower abstract submittals, the meeting was shortened by a day. After a set of fairly good papers in the morning, the afternoon was filled solely with a panel discussion (which I skipped in order to get home early).

Overall BACUS was a good conference, but it is definitely a shadow of its former self. Its not just that attendance was down (close to 600, versus something like 1000 each year during the middle of this decade), the energy level of the conference was down as well. It was worthwhile, but not exciting; fun but not one of the highlights of my year. Of course most of the malaise is due to the economy, but part is due to the state of the technology as well. EUVL is making progress, but any rational person has to be very skeptical of its eventual success. Double patterning receives too many complaints about cost, and especially mask costs (a sensitive topic at this conference), to be excited about it. Imprint will likely play important niche roles in manufacturing, but won’t save CMOS. Mapper is interesting, but may be too late to be a big player. Where does that leave us? Not having as much fun as we used to.

But moods can change quickly (like when everyone realized almost simultaneously that immersion lithography was real). We’ll see what happens this spring, where the only thing that is inevitable is a smaller Advanced Lithography conference in San Jose.

I began the second day with a four mile run on the beach, watching Venus and the crescent moon disappear as the sun rose behind the city of Monterey. Glorious. I ran with Charlie King, and had trouble keeping up with him. But then, he is so much younger than me.

Since I was way behind on finishing up the paper I had to give in the afternoon, I missed most of the morning talks. There were some very nice talks in the afternoon, but unfortunately mine was the only one on my favorite topic – line-edge roughness. My conclusion: mask writer-induced line-edge roughness cannot be ignored.

Best new product acronym: LAIPH – Luminescent Automated Image Processing Hub. The author pronounced it as “life” but it looks more like it should be pronounced “laugh”. It’s good to see that Luminescent is spending their money on engineering rather than marketing.

My broken record: I’m sorry to say that the lower number of papers at the conference has not resulted in a lower number of papers containing graphs with no numbers on the x and y axes. Why would someone show a graph in their presentation that contains absolutely no information? I don’t get it.

I enjoyed the dueling papers by KLA-Tencor and the German mask shop AMTC, where KLA showed that more measurement data was needed to know that a photomask was in spec, and the mask shop countered that less data was needed (their masks are just that good!). I found the KLA-Tencor paper (which used a non-KLA measurement tool, by the way) more convincing.

The day ended with the conference banquet, but with something missing. No entertainment. 2005 was the last year with true BACUS entertainment (skits and songs by industry insiders full of corny insider jokes). The demise of the entertainment is a long story – maybe I’ll tell it (from my perspective) someday. But I do miss it. If you have never seen it, or want to be reminded of it, check out these pictures from the days when I was a part of the cast.

It’s great to be back in Monterey! I’m at the 29th annual BACUS Photomask Technology Conference. This is its 10th year in Monterey, and unfortunately I’ve missed the last few years due to teaching commitments at UT. But I’m not teaching this fall, so I couldn’t pass on this one.

Monterey, California will always be a special place for me. I met my wife for the first time here seven years ago. And we got married in Monterey 15 months later. A beautiful town during a beautiful time of year. Oh yes, and the conference is usually a good one as well.

[Aside: BACUS is not a reference to the god of wine, despite the amount of that liquid consumed at the poster session each year. It is an antiquated acronym standing for the Bay Area Chrome Users Society – something I’ll bet that a majority of conference attendees don’t know.]

The day began with Mike Polcari, CEO of SEMATECH, giving the keynote address. He gave the standard compelling argument for collaborative research, and the standard not-so-compelling argument for EUV lithography. My favorite quote: “EUV is inevitable”. It reminds me of Mr. Smith from the movie The Matrix saying “Do you hear that? That is the sound of inevitability.” Surreal.

There was an abundance of papers coupling simulation with high resolution mask inspection images to automatically predict defect printability. I remember working on this eight years ago with Intel, back when nobody else would listen to the idea. Patience is a virtue. It could also be that every struggling OPC company with an aerial image model is desperately looking for a product that might sell.

Attendance at the conference this year is down, but not nearly as much as I would have expected. Maybe companies are anticipating the beginnings of a recovery. The mood is definitely less pessimistic (less pessimistic is the new optimistic), thinking that the worst is behind us. Let’s hope so.

Two weeks ago (has it been two weeks already?), the 2009 International Workshop on EUV Lithography began on the island of Oahu. Waikiki beach, to be exact. After two days of short courses (I taught one on Tuesday), the two-day workshop began on Wednesday.

By my estimation there were about 50 people in attendance – a very nice size for getting to know people and making connections (I did both). The workshop began with a keynote talk by Sam Sivakumar of Intel. Mostly boilerplate stuff – why EUV lithography is needed, what progress has been made, and where the gaps are. He did mention, though, that Intel’s “15 nm node”, which will have about a 30 nm half-pitch (for the SRAM) and enter high-volume manufacturing in 2013, is still ambiguous as to whether EUV or double patterning will be used. During the question and answer I pressed him on this point, and he admitted (for the first time, as far as I know) that the Intel plan of record for their “15 nm node” will be double patterning, switching “quickly” to EUVL once it is proven more cost effective.

[For the fun of it, let’s render that last statement in the ultimately concise language of corporate technospeak: The current Intel POR for 15nm HVM is DP, not EUVL.]

[Why the “scare quotes” around Intel’s “15 nm node”? With a 30 nm half-pitch, I would call this the 30 nm node. But then, I don’t have a degree in marketing.]

Samsung then gave an even more generic talk on EUV mask readiness (synopsis: not ready). Over a glass of wine later that evening, a Samsung litho engineer gave me the quick answer as to why Samsung is so interested in EUVL. After a thorough economic analysis, Samsung doesn’t believe it can make a profit producing DRAM using double patterning. Thus, without the scaling that an economically viable EUV lithography process would enable, life for the average Samsung lithographer would become (more?) hellish (meaning an unending focus on cost rather than technology). I can’t blame him for working hard to make EUVL successful.

After the keynotes, Hiroo Kinoshita of the University of Hyogo received a Lifetime Achievement Award (plaque plus a >$1000 cash-filled envelope) from the workshop organizers and EUV community. Sometimes described as the “father of EUV lithography”, Kinoshita did the first work and wrote the first paper on EUVL in the mid-1980s while at NEC. I got to know Hiroo a few years ago when he translated my Field Guide to Optical Lithography into Japanese. Thus while I’m quite biased, he’s a great guy, and I was happy to see him receive such acclaim.

The second day of the workshop began with a panel discussion on the status of EUVL R&D. I asked the question about who is doing the fundamental research needed to understand the causes of line-edge roughness (my current topic of interest, as I believe it will prove to be the fundamental limiter to optical lithography resolution). The answers were not encouraging. Later that day there were good papers by the University of Osaka in Japan and Hanyang University in Korea, but I think the answer is that not enough fundamental work on this topic is being done.

In the end, I enjoyed the workshop, and I came away as convinced as ever that Vivek Bakshi will never drive my Lotus.

It is now ten days after the workshop ended, and I am still here in Hawaii. I love the life of a gentleman scientist.

I’m back once again in the great state of Hawaii. Like last year, my nominal excuse is to attend the International EUV Lithography Workshop. And while I am still at work writing up my blog post on this topic (it is amazing how quickly I acclimate to island time), here is something to tide the interested reader over. Sally Adee, a journalist with IEEE Spectrum, was at the workshop and has been blogging on what she saw.

http://www.spectrum.ieee.org/blog/semiconductors/devices/tech-talk/i-believe-in-euvl-i-do-i-do

http://www.spectrum.ieee.org/blog/semiconductors/devices/tech-talk/intel-fellow-gunshy-about-euv-future

Wow. Did I really say all that?

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.