There were some great papers at AL on Tuesday. Here are some of my favorites. Peter Trefonas of Dow created a photosensitive block copolymer using a class of molecules called bottle brush polymers. This very early work nonetheless exhibited very good results – close to 20 nm resolution (e-beam litho) with nearly the first bottle of stuff they mixed up. The idea is simple: marry the high resolution and high sensitivity of chemically amplified photoresists with the low line-edge roughness and good CD uniformity of self-assembled block copolymers. Cool. And it looked like great fun for the chemists.
Julius Santillan of the EUVL Infrastructure Development Corp in Japan wowed the metrology conference with a high-speed atomic force microscope (AFM) that could measure 32-nm line/space features in situ during development using a carbon nanotube fiber cantilever in tapping mode. With a scan time of 2 seconds (faster is possible, he says) for a pixel size of 2.5 nm and an area of 1000nm X 750 nm, the tool made absolutely remarkable movies showing resist development and roughness formation in several different kinds of resists. The difference between PHS-based EUV resists and methacryl-based EUV resists was startling. The impact of resist development on LER was clear for all to see. Now the challenge is how best to use this new view into the physics of LER formation.
The progress in directed self-assembly (DSA) since last year has been remarkable, as evidence by the number of papers on the topic this year if nothing else. The science is advancing, the technology is advancing, and the practice is advancing. We can make very tight pitch lines and spaces with DSA, but how can we cut them to make circuit patterns? Why, with DSA of course! Even better than small lines and spaces, DSA is good at making small contact holes (though not on a super-tight pitch). So the topic that most caught my attention today was the idea of using DSA-shrunk contact holes to the cut the DSA lines. The 14/10nm node(s) could be made with two 193i patterning steps (and thus only two masks), but with significant design/layout impact. This is a very, very interesting approach. I think we will hear much more about this in the next year.
As the afternoon turned to evening I went from a panel discussion on DSA to the poster session, with a “super panel” pulling in all the conferences still in store. But when the good beer ran out at the poster session, I took the opportunity to retire for the evening and let Aki Fujimura buy me an expensive dinner (thank you, Aki!). And there is still that pesky business of getting my talks ready for Wednesday. Yes, this is life at the Advanced Lithography Symposium.
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