Zplasma in talks with ASML to develop EUV

Zplasma Inc., an extreme ultraviolet light (EUV) source start up, has been involved in talks with numerous companies in EUV lithography sector, including light source suppliers and leading lithography equipment maker ASML, as it seeks $5 million in venture capital or strategic corporate investment.

The company needs the money to develop a prototype source module which will be able to supply 200 watts at the intermediate focus of a EUV lithography scanner. This should allow a throughout of 125 wafers per hour. Manufacturing powerful sources of 13.5nm wavelength light are one of the major problems holding back the entry of EUV lithography and potentially holding back the continued miniaturization in the semiconductor industry.

Zplasma's goal is to have a prototype integrated into an ASML scanner two years from when the work started. Henry Berg, CEO of Zplasma, stated that they would like to focus on making the core EUV light-producing module, so that they may end up working in cooperation with Cymer, Xtreme and Gigaphoton without competing with them. Berg added that Zplasma is in talks with Ushio, a parent of Xtreme, and Gigaphoton as well as with lithography equipment vendor ASML Holding NV.

Zplasma, a spin-off from a University of Washington laboratory that has been working on nuclear fusion plasma containment, reckons it has learned some lessons applicable to xenon plasma for generating EUV light in a controlled manner.

The company already has a prototype that produces a "Z-pinch" plasma region 3mmsmm long by 1mm in diameter.

In an email to EETimes, Berg explained details of his company's prototype. "The plasma is generated using xenon gas and our patented flow-stabilized Z-pinch. Plasma is generated and accelerated, then assembles into a Z-pinch which is stable, lasting microseconds instead of nanoseconds. This means that each EUV pulse is longer and puts out more power. Critically, the stable end of our pinch also means it does not produce high-energy debris, which can damage the collection optics. Our current prototype was built to prove out the technology. Our product design goal is to run at 5000Hz and when integrated into a stepper deliver 200 watts of EUV light to the stepper's intermediate focus,"

Berg added: "By stretching the length of each discharge pulse, we are increasing the average EUV power produced. This allows us to decrease the instantaneous power, and reduce the operating frequency, thus simplifying the design of both the cooling system and power supply."

However, as integration with ASML could take two years from when the work starts, waiting for Zplasma could make EUV lithography as a volume production technique even later to the party than it already is. Delivery of several NXE:3300 production EUV lithography machines from ASML at a cost of more than $100 million each is expected this year for use in production, in 2013 albeit with lower power sources at around the 50-watt mark.

"The actual integration timeline is totally dependent on who is doing the stepper integration work, which is undetermined at present. If we get enough help and cooperation, it could go a lot faster," said Berg.

The Zplasma Z-pinch method can be used with different gases to produce light at different wavelengths. "While our current focus is on 13.5-nm EUV, it is quite possible that our product could be used to produce 6.7 or 6.X nanometer light," Berg said.

- Peter Clarke
??EETimes U.S.