Gigaphoton's mass production EUV light source generates EUV power

SPIE Advanced Lithography 2012, OYAMA, JAPAN: Gigaphoton Inc., a major lithography light source manufacturer, announced that its mass-production laser-produced plasma (LPP) light source, scheduled to be shipped in 2012, generated 7 watts of EUV power.

This was achieved with a Sn target (tin droplet) irradiated by a combination of solid-state laser pre-pulse and 2.7 kW, 90kHz carbon dioxide (CO2) laser main pulse. A maximum of 0.3 mJ, 27W EUV light was obtained at the plasma point running the LPP light source at 30% duty cycle for one hour. This lower level of power can be used for initial testing of current production systems. Having cleared this important milestone, Gigaphoton will continue its development program and improve the source to achieve an output of 250 W.

Gigaphoton has been working on the development of LPP light sources for EUV lithography with unique technologies, pursuing higher output and better cost-of-operation (CoO), since 2002. The company has created a number of proprietary technologies and applications, including on-demand Sn target droplet supply, a combination of solid-state laser pre-pulse and CO2 laser main pulse and debris mitigation using magnetic fields.

This announcement confirms that Gigaphoton has designed and developed an LPP light source for high-volume manufacturing by combining sophisticated elemental technologies previously verified in experimental systems. This represents a significant step toward initial shipment of a mass-production model in 2012. Gigaphoton's EUV technologies will be presented at SPIE Advanced Lithography 2012, to be held on February 12 through 16 at the San Jose Convention Center, San Jose, Calif.

The LPP light source generates energy by irradiating an approx. 20 µm (micron) diameter Sn droplet with a CO2 laser. Following the release of EUV energy, remaining Sn debris-such as Sn fragments and Sn atoms, could be deposited on the collector mirror. Because Sn ions damage the mirror's multi-layer film, lowering reflectance and power output, establishment of a debris mitigation technology to protect the collector mirror from all debris is essential.

Stable Sn droplet generation over an extended period of time, accurate positioning in three dimensions and precise timing control of the droplets are equally critical challenges in manufacturing these EUV sources for volume production.

Gigaphoton's magnetic debris mitigation technology combines the pre-pulse generated by a solid-state laser and the main pulse generated by a CO2 laser to suppress generation of any Sn fragments and neutral Sn atoms by ionizing most of the material in each droplet. These ionized particles flow to the Sn catcher magnetically and are removed, minimizing deposition and potential damage to the collector mirror.

Gigaphoton's on-demand droplet supply technology includes an innovative nozzle enabling a stable on-demand supply, timing control, and emission direction control.

As double-pattern, 193nm ArF immersion lithography approaches its resolution limit, EUV's much-shorter 13.5 nm wavelength is regarded as the next-generation lithography solution to support Moore's Law for multiple device generations to come. To field a commercially viable EUV lithography scanner, a key element is still missing from the market today, a reliable, powerful and affordable EUV energy source. Gigaphoton is committed to overcoming the remaining challenges and providing the preferred technical and commercial EUV source solution to the semiconductor industry.

Dr. Yuji Watanabe, president of Gigaphoton, said: "The achievement of first light with a mass-production technology LPP light source confirms that Gigaphoton's unique LPP light source solutions can be implemented to ensure stable performance and low-cost operation. I believe this will further increase momentum for device manufacturers to introduce EUV lithography tools as the next-generation lithography technology.

"We at Gigaphoton have already started operating a factory dedicated to initial mass-production of LPP light sources in order to meet our customers' requests for shipment in 2012. So, we remain on track to prepare for the EUV business."