Zplasma was spun out of University of Washington to develop an extreme ultraviolet (EUV) discharge-produced-plasma (DPP) light source for high-volume silicon lithography. The company was incorporated in October of 2011.

Zplasma has created a prototype that creates EUV light while keeping the plasma stable, which has never been done before. The source is differentiated by the use of a sheared plasma flow to create a flow-stabilized Z-pinch. The light-producing Z-pinch lasts 100X longer than the unstable Z-pinches produced by other DPP sources, and collapses gracefully without producing the high-energy debris that unstable pinches produce. Producing EUV light from a stable plasma has several advantages.

Stable plasma does not produce high-energy debris, which allows for long optical collector lifetimes. Short collector lifetimes are one of the critical obstacles facing today’s EUV sources.

Long stable pulses allow for operation at lower conversion efficiencies. This allows enough EUV light energy to be delivered to the stepper intermediate focus without having to use molten tin to increase efficiency. Today’s sources use molten tin and suffer from reliability problems as a result.

Zplasma’s technology produces low instantaneous power levels, while delivering high average EUV power levels. This reduces thermal stress on the electrodes, which allows for long electrode lifetimes.

A laser-produced-plasma (LPP) source uses a laser to vaporize a material, usually molten tin. A laser-discharge-plasma (LDP) source is a combination of LPP and DPP. LPP and LDP light sources require complex systems to handle the tin, and in operation produce debris, which contaminates the stepper’s optical path. DPP sources with unstable pinches also produce debris, and existing DPP sources on the market today are limited to 20 watts or less.

Cymer has shipped an LPP source producing 10 watts. Xtreme (Germany) shipped an LDP source producing 7 watts. Gigaphoton (Japan) and Adlyte (Switzerland) are also developing LPP EUV sources. All will run into the fundamental limits of LPP and LDP technologies, according to Zplasma.

ASML is furthest ahead in testing existing sources of EUV light. However these sources, mostly supplied by Cymer, which ASML recently acquired, currently sustain only 30-Watt exposure power, which is not adequate for commercial production. ASML’s specified target remains at 105 Watts or 69 wafers per hour (wph), to be achieved for 2014 microchip production.

Zplasma believes its technology is capable of producing much brighter light than competing light sources. While conventional EUV technology is still striving to produce light at 100 watts, the Zplasma device is designed to start out at 200 watts, which will enable a throughout of roughly 125 wafers per hour. Zplasma’s goal is to develop and deliver a 200 watt source in 2014 that can support EUV lithography in 2015 and beyond.

The prototype generated first light at the University of Washington in February of 2012. An exclusive license agreement to the IP and the prototype was executed in March of 2012. The company is currently seeking financial backing and a development partner to develop the prototype into a 200 watt source for HVM EUV lithography.

Henry Berg, CEO (previously an EiR at University of Washington and Product Unit Manager at Microsoft)

Uri Shumlak, co-founder (UW professor of aeronautics and astronautics)

Brian Nelson, co-founder (UW research associate professor of electrical engineering)