The SPIE Microlithography Symposium is without question the premier annual conference in the field of semiconductor microlithography. But all is not well in litho conference land. Many of the papers are simply not worth listening to. Of course, with any event this big you have to expect a range of quality in technical papers – to get the good one must accept the bad and the ugly. As the conference has grown over the years, the very good papers have stayed very good. But the bad papers have gotten worse, and the average quality of papers at the conference has steadily declined as the conference has grown. The reason for this is clear to me: an increased influence of sales and marketing goals over technical goals. With the conference’s growth in size has come a growth in influence, and a desire by many to control that influence.

What can be done to fix this problem? I’ve written a short whitepaper, A Modest Proposal, with concrete recommendations that I believe can improve paper quality. If you disagree, please let me know. If you agree, please let the conference organizers know.

I’ve just put the first batch of cartoons by Kit Auschnitt on my web page. They are part of a section I call the Lighter Side of Lithography. Kit’s cartoons are great, capturing the true geek-humor of the hard-core lithographer. Worth checking out.

You’ve got to hand it to them – those science editors at the Economist sure know how to spot a trend. In an article last week called The Cutting Edge, they showed a Moore’s law-like plot of the number of razor blades in a shaver over time. It is super-exponential, making extroplation difficult, but if the trend continues (and don’t all trends continue?) we should expect 14 blades in our razors some time between this Christmas and the year 2100.

Don’t believe everything you read. It’s a truism no rational person would disagree with. But how does it apply to published scientific research?
When teaching my graduate level lithography class at the University of Texas, I often caution my students about excessive faith in published research. “Half of what is published in the lithography literature is wrong,” I would often say. I have no data to support this claim, but after reading thousands of published papers over the last 23 years I think that number is in the ball park. I’ve recently read a published scientific paper (yes, the irony is thick here) that puts some scientific backing to the claim that most published research is wrong. John P. A. Ioannidis’s paper “Why Most Published Research Findings Are False” is fascinating – a must read for anyone involved in research. Published in the peer-reviewed open access journal PLoS Medicine (August, 2005), the paper is slanted towards medical studies, but the principles apply to all of science. When is data sufficiently strong to justify the statement that it supports either the acceptance or rejection of a proposed hypothesis? Most of the time, he claims, the data supports neither statement.
The conclusion? Science definitely moves forward, but a healthy dose of skepticism is justified.

Recently posted on the web: “SST On the Scene at the SPIE Microlithography Conference – 2006” – video interviews of numerous lithographers, where my ugly mug can be seen in two different interviews. (If looking at me too often frightens you and you need a good-looking face to compensate, check out Kurt Ronse.)

I’ve just added a new page to my web site under Published Works called Chris’s Recent Papers. The goal is to put the last few papers I’ve written here for easy access (as links to the papers or PDFs to download). If I keep writting these kinds of papers, the list should change frequently. Here is what is up there now:

What’s So Hard About Lithography?
Accuracy, speed, new physical phenomena: The future of litho simulation
Methods for Benchmarking Photolithography Simulators: Part IV
Fast lithography simulation under focus variations for OPC and layout optimizations
From Data to Decisions

A blog maintained on a personal web page is, almost by definition, self-indulgent. Benjamin Franklin once said, “Either do things worth writing, or write things worth reading.” I doubt that more than a very small fraction of bloggers fall into either of these categories. But it is the irrepressible nature of the human ego that makes the majority of us believe that we belong to the minority. With that sentiment in mind, I present this blatantly self-promoting postscript to my SPIE Microlithography Conference diary.
On day 1, before the keynote talks began, there were the obligatory awards presentations. I was one of three lithographers elected to the rank of SPIE fellow. I am certainly honored by this distinction, and hope to one day aspire to the next organizational grade – jolly good. Also this week, my new book “Field Guide to Optical Lithography” was published (it is shamelessly promoted elsewhere on my website, www.lithoguru.com/scientist/books.html). So on Tuesday morning we had an author’s book signing. You should have seen the crowds, lined up one, sometimes two deep! Fortunately, I had a ready supply of multiple pens to handle the throng. This book will no doubt be a best seller (which first requires a careful recalibration of the meaning of “best seller” when publishing in such an incredibly arcane field).
And finally, since this the third and, one would hope, last postscript to my conference diary, I’ve collected all of the conference blogs up and put them on one page at http://www.lithoguru.com/scientist/conferences/spie_diary_2006.html. For your reading pleasure.

In which direction are the prevailing microlithography winds blowing? This is always one of the most fascinating questions to ponder after attending the annual semiconductor lithography geek-fest that is the SPIE Microlithography Symposium. Almost every year some new trend can be detected. Sometimes it is subtle, as a new problem or solution starts to be explored. Sometimes it is blatantly obvious, as when a few years ago the litho crowds deserted all the other lithography talks to attend the first session on 193nm lithography. So how were the winds of change blowing this year? I detected two gentle breezes, not too stiff, but quite obvious.
The first was a breath of fresh air for EUV. Yan Borodovsky in his keynote speech probably didn’t reassure a skeptical audience by showing how Extreme UV Lithography needed to improve by “only” 11 orders of magnitude before it was ready for production. Intel may be the biggest cheerleader for this next generation lithography, but the facts are the facts despite the spin. However, the next day ASML made up for lost ground by giving a well-received review of their EUV scanner development program – not to the believers in the Emerging Lithography conference, but to the life-long skeptics in the Optical Lithography conference. Personally, I still think that EUV technology is the next X-ray Lithography, doomed to failure by unforgiving physical realities. But it won’t be due to lack of effort, and if anyone can make it work it will be the industrious Dutchmen at ASML.
The second breeze felt warmer on my skin (optical bigot that I am), for it flowed along a path that allows 193nm to keep going past the 45nm half-pitch. High index fluids and materials can get you so far. Then what? Double printing, where two larger pitch patterns as interspersed to create a smaller pitch pattern, is getting serious attention. Of course, nobody likes to even think about doubling the cost of an already expensive critical lithography step. And the overlay challenges are formidable. Still, double patterning may first prove valuable as a process development vehicle, enabling device and process learning before other lithographic alternatives are available. Then, efforts towards making the technique production worthy might be successful. There is always huge momentum behind incremental improvements to our existing technology. I am hopeful, if not optimistic, that double patterning will eventually become mainstream.