Attending a meeting like Advanced Lithography I always have one hope: that I will listen to a paper that makes me say “wow!” After the first two days there were no “wow” moments. But then it happened for me on Wednesday. It was the first resist session in the morning, and I saw why Greg Wallraff and Bill Hinsberg’s group at IBM Almaden Research is so unique. Linda Sundberg gave a paper that I found hard to imagine coming from anyone else’s lab. The problem was an old one, though with a modern twist: how big an effect is developer depletion, and how can we separate that affect from chemical flare (acid that evaporates from one spot on the wafer and then redeposits nearby). What made the paper so good was the approach – she didn’t ask “what’s the easiest way to figure this out”, but asked “what’s the best way to figure this out.” They built a flow-cell to send a very controlled, small volume of developer sequentially across a line of exposed resist patterns to see how CD varied with order of contact with the developer. Sunberg happily described the early failures of this flow-cell, the redesigns that gradually improved it, and how the final version worked. It was a good idea followed by systematic attacks on the inevitable problems leading to an answer to a question that we’ve been asking in this industry for 20 years. Outstanding work.

There were also very good papers by Vivek Prabhu of NIST and Vassilios Constantoudis of Demokritos (Greece) in that same session. I walked out for the coffee break remembering why it was I love this conference. Later that morning I saw a good paper by Kedar Patel of SanDisk on comparing LWR measurements for different next generation lithography (NGL) approaches. His data was excellent, but his conclusion that every NGL approach can meet the ITRS roadmap specifications for LWR was inexplicable. I always enjoy discovering a new student, coming to the conference for the first time, who has become turned on by lithography. Alessandro Vaglio-Pret is getting his PhD at Imec and he gave a wonderful talk on roughness post-treatments, a topic many have discussed but only Alessandro provided reliable data for.

I gave a paper on my approach to modeling line-edge roughness in the afternoon (it’s always fun to give a talk), then finally gave up on attending papers for the rest of the day. I was winding down my brain and turning the conference into a social event (one of its other important uses). I talked to so many people at the poster session that I forgot to see any posters. I hit up a few hospitality suites in the evening, then went to bed thinking that this was a very good day.