It’s been a long time since a lithography conference was just about lithography. Last year TSMC gave a talk that described problems they were having with EUV lithography and ASML’s stock price went down 5%. Yesterday (Monday), Tony Yen of TSMC gave a talk describing very nice progress on source power and throughput and ASML’s stock price went up 5%. Is it a good thing that so many stock analysts attend these talks? It doesn’t help that ASML had a press release ready to go and sent it out just minutes after Tony had finished (Title: “ASML announces new high mark for EUV productivity; TSMC images more than 1000 wafers in a single day”). About half a dozen analyst blogs were crowing about the importance of what Tony said, one even counting the number of times he mentioned KLA-Tencor. This puts a lot of pressure on scientists and engineers giving technical talks to focus on things that aren’t technical, and that is pressure we do not want or need. I guess there is nothing to be done – it is just reality. But I don’t like it.

My Tuesday was far from such earth-shaking events. I buried myself deep in the rough landscape of stochastic resist response, line-edge roughness (LER), and how to measure noise. Fascinating, but don’t expect a stock analyst to be parsing any of my words on the topic. There were several attempts to simulate the impact of roughness on SEM linewidth measurement, with important insights. Richard Lawson of Georgia Tech showed that roughness on a vertical feature sidewall produces SEM images that look just like smooth sidewalls that are sloped. There is a lot of information in an SEM image, but maybe less than we hope. My 8am paper was about how to extract the most information possible from an SEM image, and that our current measurement algorithms don’t take advantage of everything we know about how those images are generated. As I said Monday night, build better metrology. We desperately need it.

My third and last paper was Tuesday afternoon, where I gave a mathematical proof that post-lithography process smoothing techniques won’t work, at least not as well as we need them to. Like all mathematical proofs, its validity will depend on the validity of my assumptions. I hope that those who believe in the efficacy of post-process smoothing will design experiments that directly challenge those assumptions instead of just showing SEM images and reporting reduced three-sigma roughness numbers.

The conference is half-way done!

If you walk through the crowds this year, you know the symposium is well attended. We have about 50 less papers this year than last, but about the same number of attendees – on the order of 1,700 technical attendees and another 800 or so who just come to the exhibits. Short course attendance was up about 25% from last year. A very healthy and dynamic conference.

We began our first day with the awards ceremony, and a very rare “career achievement” award. Andy Neureuther and Bill Oldham were acknowledged for their “career long contribution to the art and science of lithography” through their lithography modeling efforts at the University of California at Berkeley. Andy was a co-author of some of the original 1975 Dill papers (the most famous papers in lithography, in my opinion) and Andy and Bill, along with their students, published the SAMPLE simulator in 1979. Their SAMPLE group made numerous important contributions to lithography over the last 35 years, and of course the many great students they have graduated continue to multiply their influence. As Symposium Chair Mircea Dusa said, this work was a “defining moment, when lithography went from an art to a science.” The award was made “in deep appreciation for your 40 years of visionary guidance and dedication to SPIE society and lithography community.” Congratulations Andy and Bill!

Ralph Dammel, CTO of AZ Electronic Materials, was the recipient of the 12th Frits Zernike award (full disclosure – I nominated him). I learned a tremendous amount from Ralph’s 1993 book on DNQ/Novolac resists, and learned to appreciate sweetbreads and German coffee when I visited him in Frankfurt about 25 years ago. A well-deserved award (for the lithography, not the sweetbreads).

We have five new Fellows of SPIE in our community as of Monday: Luigi Capodieci, Bernd Geh, Moshe Preil, Masato Shibuya, and Obert Wood. GlobalFoundries almost swept the ranks! Congratulations to all of you.

The plenary session was a mixed bag. Alan Willner gave a nice overview of the National Photonics Initiative, an “alliance” of industry, academia, and government that includes SPIE and that began in 2012. The goal of the NPI is to drive US investment in photonics (read: get the US government to spend more on photonics). Photonics, like many fields of science that border technology, seems to have a case of Moore’s Law envy.

The talk by Tsu-Jae King Liu of UC Berkeley was one of the best plenaries ever. With power as the current limiter of CMOS performance scaling, she proposed a couple of very innovative solutions. The use of micro-relays was especially intriguing. I’ll be following developments in that field going forward.

I have been out of corporate America too long to appreciate Xiaowei Shen’s final plenary talk on the “internet of things”. It was so full of IBM-speak that I could barely understand it.

When the regular conference talks began at 11am I had the familiar problem of wanting to be in multiple places at the same time. I missed more worthy talks than I attended. Gerg Yeric of ARM showed me how little I know about design-manufacturing interactions and how hard scaling is getting independent of lithography. He noted that when we shrink, some of the SRAM cells in logic designs are moving from 6 transistors to 8, 10, or even 18 transistors to store one bit in order to keep the cells both fast and reliable in the face of variability. It makes you wonder if cost per transistor is a useful metric to assess the value of shrinking.

Changmoon Lim of SK hynix gave a talk on challenges for EUV insertion into high-volume manufacturing (HVM), a perennial topic at this conference. The Hynix experience on the NXE:3100 EUV tool from ASML was about slow learning. The tool was installed in the summer of 2011 and over three years the throughput went from 2 wafers per hour (WPH) to 7 WPH, and tool availability went from 25% to 75%. Learning is picking up with the installation of their NXE:3300, though he gave little data. A 2xnm generation DRAM split lot with one layer printed on EUV produced comparable yield to 193i, but they had to use an exposure dose much higher than the goal of 20 mJ/cm2 to achieve that yield (when I asked, he wouldn’t tell me the exact dose used).

I missed Tony Yen’s talk about EUV progress at TSMC – I was busy giving a talk of my own. I’m told he described the very fast progress that source power has made in the last year, going from 20W to 40W, and more recently to 80W, installed on a TSMC tool. I also missed Todd Younkin of Intel and the idea of bottoms-up growth of metal vias next to cuts filled with dielectric to improve overlay. He told me later than much work remains on this idea, but it sounds very promising.

Toshiaki Ikoma, CTO of Canon, gave an overview of their new nanoimprint lithography (NIL) tool, claiming the tool was “now available” and that Canon “will be back to the leading lithography company again.” We’ll have to wait and see. And we’ll have to wait to see the data that support these claims during other NIL talks this week.

The day ended with a panel discussion on the metrology challenges of 3D devices. I was on the panel, but since I know nothing about the metrology challenges of 3D devices, I gave a speech on a different topic. You can find my speech here: http://www.lithoguru.com/scientist/essays/Metrology.html.

A general complaint about panel discussions: the standard format that we almost always use doesn’t work. We should abandon it. This format involves posing a number of momentous and difficult questions, and telling each panelist to prepare a 5 minute talk on those questions. Of course, the panelists use powerpoints (most of us are barely able to talk without powerpoint, and I suspect the audience is barely able to listen without powerpoint as well), and each one averages 10 minutes. Our scheduled 90 minute panel had only 30 minutes of audience questions at the end, but that was only because we went 20 minutes over the allotted time. Through no fault of the fine panelists on stage with me, it was a truly boring experience. How can we make panels better? Give the panelists at most one minute (and no slides) to make an introductory statement, or better yet no introductory statement. Then go right into questions, alternating between moderator and audience questions. Make sure it is fun, and not a mini conference session. Also, beer helps.

My favorite quote of the day: “Double patterning was thought to be a bridge between immersion and EUV, we just didn’t realize how long the bridge would be.” – Changmoon Lim, SK hynix

I have to admit that I’m a sucker for round numbers. Five, ten, twenty five year anniversaries will always find me waxing nostalgic. Well, today is a round number for me. I’ve been on this planet for 20,000 days. The 10,000 day mark passed without notice, but somehow I realized that 20,000 was coming. I think I’ll quit working early and have a beer.

You’ve heard this advice many times before, and it comes out in full force during graduation season:  Follow your passion.  Whether it is picking a major in college or starting on a career path after graduation, following your passion is said to lead to self-satisfaction and the chance for greatness.  Picking the major your parents advise, the one with “decent career prospects”, will lead to a soul-sucking job mired in middle management and eternal regret.  The choice seems obvious.  “Follow your passion” is inspiring advice.

But it is good advice?

The first problem is that many teenagers are passionate about things that don’t much matter:  video games, music, and texting (and sexting) their friends.  I don’t have a problem advising a kid to become a doctor if they are passionate about finding a cure for breast cancer.  But for every highschooler whose passion drives them towards filling an important societal need, there are many, many others who want to be pop stars.  And most (or maybe all) of those kids would be far better off following a different path than the passion-laden American Ideal route to fame and fortune.

Others have criticized the “follow your passion” or “do what you love” advice as elitist (Miya Tokumitsu, Slate, January, 2014) or as ignoring the important role of self-sacrifice and duty in building character (Gordon Marino, New York Times, May 18, 2014).  My criticism is more pragmatic:  for the most part, following your passion doesn’t work.

My own experiences are probably pretty typical of most post-college careers.  I didn’t follow a path dictated by my passion for the simple reason that I didn’t follow any path.  Most of what came my way was random, out of left field, and most of my choices were reactive, even when they looked and felt proactive.

I recently came across a paper I wrote in my senior year of college discussing my future plans.  At the time I wanted an academic career – graduate school followed by teaching and research.  I wrote in a mocking tone that the last thing I would ever think to do was get a government or corporate job or start my own business.  But life has a well-known way of getting in the way of aspirational plans.

A girl turned my interests away from studying to marriage, and finances ended the possibility of continued graduate school.  I took the first job I could find – with the federal government.  Eight years and one divorce later I was starting my own business.  Ten years after that I had sold the business and was a corporate VP.  A late, new start at forming a family and having children prompted an end to my corporate life and now I find myself full circle, teaching part time at a university and pursuing my own research ideas on my own terms.

And after every turn on that wild ride I found something worthy of my passion.

I can’t image being any place different from where I am now, and I can’t imagine getting here in any other way but the actual crooked path that lead me here.  But this reflects nothing more than a lack of imagination.  The fact is I could have gone in hundreds of other directions and turned out just as well, and had as much fun along the way.  The reason is simple:  rather than take the path that followed my passion, I became passionate about whatever path I happened to take.

Make no mistake, not every step on my life journey was a pleasant one.  In fact, some of my turns can only be described as wrong ones.  That is not failure, that is just life.  Like everyone else, I lived a life with constraints and made the best of them.  But there was no time along that path where I couldn’t find a reason to take pride in what I was doing or could accomplish: digging ditches to pay for college; studying hard for a class I wouldn’t have chosen but found myself taking anyway;  working in a decidedly unglamorous government bureaucracy; taking a second job to help make ends meet.  In every case, there was something to learn, something to care about, something to engage my intellect and heart.

The “follow your passion” advice makes a critical set of unstated assumptions: that we have one or very few passions, that we already know what they are (or can quickly go about discovering them), and that the only thing blocking our way to self-actualization is a lack of commitment to those passions.  For almost everyone, all three assumptions are wrong.

I have found that there is an almost infinite variety of things that can ignite my passion.  I am by nature curious, and every time I look closely at something I find it to be worthy of even closer examination.  Do you find accounting boring?  I promise you, it is only because you don’t know enough about accounting.  As a small business owner I had to learn enough accounting to survive, but when I moved to a large corporation I saw how seemingly mundane accounting choices rapidly distorted the ethical choices made daily by upper management.  Passion was there waiting to be discovered.

My advice to high school graduates facing an uncertain college experience?  Take the idea of a liberal education seriously and learn how to think.  Prepare yourself not for a career, but for career potential.  Accept that your future path is unknown.  My advice to the new batch of college graduates?  Following your passion is all well and good, it just usually doesn’t work out.  Instead, recognize that there is a near-infinite number of opportunities facing you at every moment, just waiting for you to care.  Start caring.  Be passionate about whatever path you happen to follow.  This doesn’t guarantee success and happiness, but it gives you the best shot.

Or, to use the words of Stephen Stills, “if you can’t be with the one you love, honey, love the one you’re with.”

In general, infrastructure issues are not interesting.  I’ve been having problems with my blogging software, Nucleus, as that package has become increasingly marginalized and out of date.  Eventually, the anti-spam capabilities stopped working and I had to turn off the ability to add comments in order to survive.  Thus began the long saga of converting to WordPress (a very tedious task converting all the old posts to the new platform).

That transition is finally complete.  Maybe complete is too strong a word, as I am sure that changes and tweaks will be required as I use this new platform.  But in any case, I hope that my blogging, and your reading and commenting of same, will now be much smoother.

I’ve been meaning to do this for some time, but the drudgery of the task kept pushing back at me. But now it is done – 183 published papers on lithography (authored or coauthored by myself) are all available on my webpage and downloadable. Here is the link:

http://www.lithoguru.com/scientist/papers.html