Development of a 5 kHz Ultra-Line-Narrowed F2 Laser for Dioptric Projection Systems.

Abstract

The roadmap of semiconductor fabrication predicts that the semiconductor market will demand 65 nm node devices from 2004/2005. Therefore, an Ultra-Line-Narrowed F2 laser for dioptric projection systems is currently being developed under the ASET project of "The F 2 Laser Lithography Development Project". The target of this project is to achieve a F2 laser spectral bandwidth below 0.2 pm (FWHM) and an average power of 25 W at a repetition rate of 5 kHz. The energy stability (3-sigma) target is less than 10%. An Oscillator-Amplifier arrangement at 2 kHz was developed as a first step of an UltraLine-Narrowed F2 laser system. With this laser system, we did the basic study of the synchronization technology for line narrowing operation using two system arrangements: MOPA (Master Oscillator I Power Amplifier) and Injection Locking. Based on this experience we have developed the 5 kHz system. With the 5 kHz Line-Narrowed Injection Locking system, we have achieved a spectral bandwidth of < 0.2 pm with an output energy of > 5 mJ and an energy pulse to pulse stability of 10% . The feasibility of a 5 kHz UltraLine-Narrowed F2 Laser for Dioptric Projection Systems has been demonstrated.