Takayuki Yabu

CO2 laser-produced Sn-plasma source for high-volume manufacturing EUV lithography

We are developing a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography. The light source is based on a high power, high repetition rate CO2 laser system, a tin target and a magnetic ion guiding for tin treatment. The laser system is a master oscillator power amplifier (MOPA) configuration. We have achieved an average laser output power of 10 kW at 100 kHz by a single laser beam with good beam quality. EUV in-band power equivalent to 60 W at intermediate focus was produced by irradiating a tin rotating plate with 6 kW laser power. This light source is scalable to more than 200 W EUV in-band power based on a 20-kW CO2 laser. Collector mirror life can be extended by using droplet target and magnetic ion guiding. Effectiveness of the magnetic ion guiding is examined by monitoring the motion of fast Sn ion in a large vacuum chamber with a maximum magnetic flux density of 2 T.

Characterization and optimization of tin particle mitigation and EUV conversion efficiency in a laser produced plasma EUV light source

A laser produced plasma (LPP) extreme ultraviolet (EUV) light source of 13.5 nm has been developed for next generation lithography. Sn plasma is an efficient generator of 13.5 nm EUV light. On the other hand, deposition of Sn particles which strongly affects EUV collector mirror lifetime is a critical issue for long-term stable operation of the high-power EUV light source. In this paper we describe about the optimization of tin debris mitigation with a compact EUV generation system. We observe almost all of Sn fragments generated after a pre-pulse irradiation are vaporized by a main CO2 pulse laser with a droplet of 20 μm in diameter. An EUV conversion efficiency (CE) of 3.4% at a maximum is obtained for the 20 μm droplet. These results indicate the debris mitigation can be achieved without degradation of the high EUV CE.

Magnetic field for efficient exhaustion of CO2 laser-produced Sn plasma in EUV light source

We are developing a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography. The light source is based on a high power, high repetition rate CO2 laser (10.6μm) system, a tin (Sn) target and a magnetic ion guiding for Sn treatment. We evaluated the characteristics of Sn debris generated by a CO2 laser produced plasma. Experiments were performed with bulk Sn-plate targets and Mo/Si multilayer mirror samples were used for debris analysis. We observed very thin and uniform Sn layers of nano/sub-nano size debris particles. The layer deposition rate at 120mm from the plasma is, without magnetic field, about 30nm per million shots. The fast Sn ion flux was measured with Faraday cups and the signal decreased by more than 3 orders of magnitude on application of a magnetic field of 1T. The Sn deposition on the Mo/Si multilayer mirror decreased in small magnetic field space by a factor of 5. In a large magnetic field space, the effectiveness of the magnetic guiding of Sn ions is examined by monitoring the fast Sn ions. The ion flux from a Sn plasma was confined along the magnetic axis with a maximum magnetic field of 2T.

Key components development progress updates of the 250W high power LPP-EUV light source

Gigaphoton Inc. is developing a CO2-Sn-LPP EUV light source based on unique and original technologies including a high power CO2laser with 15 nanosecond pulse duration, a solid-state pre-pulse laser with 10 picosecond pulse duration, a highly stabilized droplet generator, a precise laser-droplet shooting control system and a debris mitigation system using a magnetic field. In this paper, an update of the development progress of our 250W CO2-Sn-LPP EUV light source and of the key components is presented.

Laser produced plasma light source for HVM-EUVL

A major technical challenge of an extreme ultraviolet (EUV) light source for microlithography at 13.5 nm is the in-band power requirement of more than 115 W at the intermediate focus. The solution for HVM EUV lithography is a laser produced plasma light source with a cost effective CO2 drive laser and a high conversion efficiency Sn target. To demonstrate this, a LPP source is developed for high volume manufacturing EUV lithography which is based on a high power CO2 MOPA (Master Oscillator Power Amplifier) system and a tin target. It is concluded that the CO2 laser driven Sn light source is the most promising candidate for HVM EUVL due to its scalability, high efficiency and long collector mirror lifetime.

Small Field Exposure Tool (SFET) Light Source

A laser produced plasma light source for a small field exposure tool (SFET) has been developed at the EUVA Hiratsuka R&D center. The light source consists of the following components: The drive laser of the xenon plasma source is a short-pulse, high-power KrF laser that has been developed in cooperation with Gigaphoton Inc. and Komatsu Ltd. The laser has an unstable resonator and produces a maximum output power of 580W at 4kHz repetition rate. The xenon target is a 50 micrometer diameter liquid jet with a speed of about 35 m/s. The source has been designed to generate 0.5W in-band power at the intermediate focus (IF) at a collecting solid angle of pi sr. The source includes automatic control, e.g. jet and plasma position control, and an electrical interface for the exposure tool. The performance of the source at IF has been evaluated by Canon Inc. This paper explains source performances. Especially, results of IF parameters like image size, position stability and out of band radiation are presented.

Key components development progress of high-power LPP-EUV light source with unique debris mitigation system using a magnetic field

Gigaphoton Inc. has been developing a CO2-Sn-LPP (LPP: Laser Produced Plasma) extreme ultraviolet (EUV) light source system for high-volume manufacturing (HVM) semiconductor lithography. Original technologies and key components of this source include a high-power carbon dioxide (CO2) laser with 15 ns pulse duration, a short wavelength solid-state pre-pulse laser with 10 ps pulse duration, a highly stabilized small droplet (DL) target, a precise DL-laser shooting control system and unique debris mitigation technology with a magnetic field. In this paper, an update of the development progress of the total system and of the key components is presented.