Category Archives: Microlithography

Semiconductor Microlithography

Sharing a Mid-Life Crisis

David Pan, a friend of mine and professor at UT Austin, told me recently “Moore’s Law isn’t dead – it’s just having a mid-life crisis.” Although I wrote an article a few years ago provocatively titled “The End of the Semiconductor Industry as We Know It”, I think David is right – our industry is in mid-life crisis. I can relate.

Gordon Moore penned his famous law in 1965, observing a doubling of the number of the transistors on a chip since the birth of the integrated circuit in 1960. Now it just so happens that I was born in 1960. I certainly don’t claim any cosmic connection to continuous semiconductor improvement due to this coincidence of birth dates, but it does mean that me and the technology driver of the Information Age share at least one thing – we are both getting old.

Now I certainly don’t feel ‘old’, or that my useful days are behind me, but I’m not young either. I can’t pull all-nighters anymore, they way I used to when I could start and finish a conference paper 12 hours before I gave it. I’m unwilling to put my life on hold when a customer calls and says he needs something yesterday. I can’t work in the fab – that’s a young person’s job. And yes, the cries of “mid-life crisis” could be heard from all of my friends when I bought that Lotus sports car last year. I’m definitely older, but I like to think that I’m wiser too, and that this wisdom is more than enough to make up for a little slowness in step. But is the same thing true of the IC industry? It better be, or things will get pretty ugly fast. Working harder and faster because we have to keep with Moore’s Law is not good enough any more. The IC industry took off because the early pioneers took the science of semiconductors and turned it into technology. For that technology to keep going, we’ll have to bring in a whole bunch of new science. Most of that science will come from the universities, unlike in the past when most innovations came from the IC companies. Increased support for univeristy research is needed now, and hopeful it is not already too late.

Moore’s Law is getting old – let’s hope it gets wise as well.

Grant Willson and a Drunk Driver

I just got back from visiting Grant Willson in the hospital here in Austin. One week ago, while driving to pick his wife up at the airport, he was hit head-on by a drunk driver.

Almost everybody working in the field of microlithography knows of Grant Willson. While at IBM he invented chemically amplified resists and has subsequently received every award I can think of for that work, including SPIE’s Frits Zernike Award for Microlithography, our field’s highest honor. For more than a decade he has been teaching at the University of Texas at Austin and his irreplaceable leadership in the education of scores of students has produced results that may even eclipse his scientific contributions. For those of us lucky enough to know Grant personally, he is affable, giving, and a man of the highest possible integrity.

The accident banged him up badly, crushing parts of his hip. When I saw him last Thursday, less than two days after the accident, he was in good spirits, but in obvious pain. Today he was much better, and he should be heading home soon (in typical Willson fashion, ahead of schedule). The hope is that after 2 – 3 months of physical therapy (learning how to walk again) he’ll be right as rain.

Best wishes for a speedy recovery, Grant.

David W. Mann and GCA

If you have poked around my site much, you may have noticed a section on the history of semiconductor lithography. It still needs a lot of work, so anyone who has any good information to share, I would appreciate it.

In particular, I’m trying to find out the year and circumstance around the purchase of the David W. Mann Company (maker of photorepeaters for mask making) by GCA (who eventually turned the technology into wafer steppers). Any and all help would be appreciated.

How to make SPIE papers worth listening to (a modest proposal)

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.

Moore’s Law for Razor Blades

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.

Wrong Research Results

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.

New web item – my recent lithography papers

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

SPIE Microlithography Conference, Post Script #3

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, 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 For your reading pleasure.