Feasibility study on the impact of high-power EUV irradiation on key lithographic elements

EIDEC has built a high-power EUV irradiation tool equipped with a laser-produced plasma source to investigate the effect of EUV power and pulsed irradiation on the resist outgassing and durability of the mask and pellicle elements. In this paper, we discuss the feasibility study on the impact of high-power EUV irradiation on key elements through the application of a high-power EUV irradiation tool. The equipment comprises a laser-produced plasma source similar to those used in presently available EUV scanners and relay mirrors which facilitates the EUV irradiation on the sample plane. The equipped laser-produced plasma source has lower power at the intermediate focus than those expected in future high-volume manufacturing EUV scanners. However, with fewer relay mirrors compared to these EUV scanners, sufficient EUV power density is emulated on the sample plane i.e. EUV power equivalent to what is expected in future high volume manufacturing EUV scanners can be obtained. The basic design configuration and performance of the laser-produced plasma source and the entire system are discussed. Tests for investigating the effect of EUV power density on the outgassing and durability of mask blanks have commenced, and the preliminary results are presented in this paper.