SANTA CLARA, Calif. -- At the SPIE Microlithography conference, the star of the event was obvious: immersion lithography.
But there were also other significant announcements at SPIE, especially in the extreme ultraviolet (EUV) lithography camp. Intel Corp. and developers of power sources made separate announcements in the arena.
For example, making its latest move in EUV, Intel this week announced an equity and development deal with Italy's Media Lario International S.A., a supplier of optical components for EUV and other applications.
Under the terms, Intel Capital will make an undisclosed investment in Media Lario, based just north of Milan. The agreement is also designed to accelerate Media Lario's research and development activity for EUV components. EUV is a next-generation lithography technology, which is geared for the 32-nm node.
Media Lario specializes in high-accuracy, reflective optical components, which will be used in EUV applications. The company was a key contributor to the success of the European Space Agency XMM mission, which resulted in the launch in 1999 of the most powerful X-Ray telescope ever built.
"These agreements will help accelerate the development, and commercialization, of high accuracy reflective mirrors and mirror systems to meet the ever-stringent optical performance and cost of the current and next generation lithography equipment," said Giovanni Nocerino, president and CEO of Media Lario, in a statement.
"Developing EUV optics technology to enable affordable EUV source and lithography systems for high-volume manufacturing on the 32-nm node in 2009 is a key challenge at Intel," said Peter Silverman, Intel Fellow and director of Intel's Lithography Capital Equipment Development, in a statement. "These agreements will help enable Media Lario to focus on the development of EUV optics technology to meet the technology performance and cost requirements."
The move represents the latest investment by Intel in the EUV arena. Last month, Cymer Inc. signed a $20 million development agreement with Intel to accelerate its development of production-worthy EUV lithography light sources. Intel's move to invest $20 million in Cymer Inc. is part of a major effort to maintain the chip giant's previously stated goal of bringing EUV lithography tools into production for the 32-nm node by 2009.
At the same time, ASML, Canon, and Nikon are developing EUV tools, it was noted.
Finding the source
Meanwhile, results reported at a meeting of lithography engineers held at the Santa Clara Hilton on Sunday February 22, 2004, showed that many of the challenges facing EUV are gradually being overcome, according to International Sematech (ISMT), which organized the meeting.
In particular Philips Extreme reported an EUV source at 20 watts, ISMT said, nearly doubling the previous best source power reported for EUVL.
Besides EUVL source power, topics addressed at the 'EUV Source Workshop' were: improved debris mitigation and lengthier collector lifetimes.
More than 60 companies were represented by 130 lithography executives and engineers at the meeting. Attendees were shown experimental results for EUV sources that can produce nearly one-fifth of the power that is considered necessary for commercial EUV lithography systems in high volume manufacturing. Previously EUV sources had been limited to about one tenth the 115-W optical power needed for volume wafer throughput.
The newer EUV sources are demonstrating significantly better control of debris and pushing collector lifetimes toward practical ranges, although considerable progress still needs to be made in this area, according to ISMT.
"EUV sources clearly are moving forward, and our biggest obstacles for achieving EUV sources suitable for high volume manufacturing are being addressed aggressively," said Vivek Bakshi, workshop chairman and ISMT EUV source project leader, in a statement. "The progress shown in the high-quality presentations in the workshop have given us many reasons to be optimistic about EUV's potential for high volume manufacturing," he added.
One method to produce EUV light, with a wavelength of 13.4-nanometers, is to magnetically compress xenon or tin to very high temperatures. This technology is called "pinch plasma" or gas discharge produced plasma (GDPP).
A second method to generate EUV light is to bombard a target of tin or xenon with a high power laser; a technology called laser-produced plasma (LPP). In both approaches, the resulting EUV light is gathered by a collector lens system that projects it to an area called the intermediate focus, whence it can be directed to a wafer to print semiconductor patterns.
It is now considered that the amount of EUV power at the intermediate focus must be approximately 115 watts, whereas experimental systems a year ago were generating only 5 watts. In addition, the "debris" of high-energy ions and neutral particles, which are produced from very hot xenon or tin, must be controlled to prevent damage to components of EUV sources and optics. Also, the collector must be able to withstand billions of energy pulses and impact from debris without breaking down, or else it will have to be replaced too often and production costs will be prohibitive.
EUV source developer Philips Extreme described the output of more than 20 watts from a tin-based plasma pinch source, ISMT said.
ISMT added that Philips Extreme had also shown the ability to control debris generation extending the advantages of using tin and making it more competitive with xenon. The diminished level of debris, had led Philips Extreme to state at the workshop that within a year the company expected to have produced a source with a collector lifetime of more than 1.5 billion pulses, ISMT added.
Meanwhile, Xtreme Technologies presented an EUV source that generates 15 watts of power at the intermediate focus using xenon, with a collector lifetime of more than 100 million pulses. Xtreme is supplying Exitech Ltd. with an EUV source for its Microstepper system, which ISMT plans to use as part of an EUV resist development program in Albany, New York, ISMT said.
At another presentation at the workshop stepper manufacturers Nikon, Canon and ASML declared jointly that EUV source components must have a lifetime of 30,000 hours.
They clarified the issue by saying that while optics must maintain 90 percent of reflectivity for 30,000 hours of light-on operation, this requirement applies to optics that lie after the intermediate focus and not to the source components that are located before the intermediate focus.
This re-stated requirement allows pre-intermediate focus EUV source components to have lifetimes of less than 30,000 hours. In other presentations laser-produced plasma (LPP) sources were reported with up to 4 watts of power, ISMT said.