Gigaphoton Inc. has been developing a CO<sub>2</sub>-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 (CO<sub>2</sub>) 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.
In advanced lithography processes, immersion lithography technology is beginning to be used in volume production at
the 45-nm technology node. Beyond that, double-patterning immersion lithography is considered to be one of the
promising technologies -meeting the requirements of the next-generation 32-nm technology node. Light source
requirements for double patterning lithography tool are high power and high uptime to enhance economic efficiency, as
well as extremely stable optical performances for high resolution capabilities.
In this paper, the GT62A, Argon Fluoride (ArF) excimer laser light source which meets these requirements is introduced.
The GT62A has an emission wavelength of 193-nm, a power output of 90 W and a repetition rate of 6,000 Hz. The dose
uniformity of the GT62A was improved for reduction of Critical Dimension (CD) variation and better Critical
Dimension Uniformity (CDU). A stable wavelength and a spectrum bandwidth of the GT62A satisfy the requirements of
the high resolution lithography tools which need the steady focus stability. In addition, we verified by simulation that the
spectrum bandwidth control in the GT62A contributes to Depth of Focus (DOF) enhancement. The new technology for
the light source and detailed optical performance data are presented.