At SPIE Advanced Lithography, Cymer announced some serious progress in EUV source development, one of several highlights. The latest results provided 40W of power in runs over 8 hours that mimicked full productions conditions including dose control. As far as I can tell, 40w translates to around 30 – 300 mm wafers an hour.
By Michael P.C. Watts
At SPIE Advanced Lithography, Cymer announced some serious progress in EUV source development, one of several highlights. The latest results provided 40W of power in runs over 8 hours that mimicked full productions conditions including dose control. As far as I can tell, 40w translates to around 30 – 300 mm wafers an hour.
The Cymer source uses a CO2 laser with 3 amplifiers to produce a very intense 15 kW 10 um wavelength light source with a 100 um spot size. The laser hits a 30 um diameter molten tin drop to create a EUV pulse. Most of the recent progress centers on first making the tin drop bigger by hitting it with a prepulse that swells the drop to a similar size to the CO2 laser spot. The second feature is a control system that times the laser to hit the moving drop, and moves the laser spot around in 2 axes to follow the stream of dots .
Pre-pulses have become a popular idea in high energy sources; they are used in laser fusion and in proton laser systems. Apparently, the prepulse idea applied to EUV was proposed at the International Congress on Plasma Physics 2008, by a team from Institute of Laser Engineering, Osaka University. They had been working on using tin droplets as a EUV source.
From Institute of Laser Engineering, Osaka University, Presented at International Congress on Plasma Physics 2008.
In the past 4 months, Cymer reported the following progress ; a 2x increase in power, a 5x improvement in control, and 2x in duty cycle, all a result from making sure that the laser spot hits the droplet. The result is dose control of 0.2% at better than 90% duty cycle, which are real production numbers. They are running a test laser and are planning on retrofitting existing installations this year. They also had data on up time from field systems, and collector lifetime improvements from barrier coatings and using a hydrogen blanket to protect the collector.
All in all, a really impressive set of new data, that I am sure will encourage EUV watchers.
However, there is still a long way to go to a system that can justify the total EUV system cost of somewhere north of $60M. Cymer showed their roadmap to a 250W (125 wph ?) solution. They are planning on increasing the number of amplifiers to 4, increasing the efficiency of the amps, and have shown a further 1.5 x in EUV conversion efficiency in the lab. Apparently, the next generation systems will ship with 4 amplifiers and will be upgradable to 250W.
When they are done, the light source is a box with an eye popping wall plug burst power of 0.5 mega-watts ! As for price … they would not say …. my guess is if you have to ask you probably cannot afford it !
The other eye popping news was that I gather that soon there will be there about 1000 people from both ASML and Cymer working on the source. I suspect that this partially explains the acquisition of Cymer by ASML…… They are jointly seriously committed.
About the Author
Mike Watts has been patterning since 1 um was the critical barrier, in other words for a longtime. I am a tall limey who is failing to develop a Texas accent here in Austin. I have a consulting shingle at www.impattern.com.
My blog “ImPattering” will focus on the latest developments in the business and technology of patterning. I am particularly interested in trying to identify how the latest commercial applications evolve.
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