TNO is developing a High Power Adaptive Mirror (HPAM) to be used in the CO₂ laser beam path of an Extreme Ultra- Violet (EUV) light source for next-generation lithography. In this paper we report on a developed methodology, and the necessary simulation tools, to assess the performance and associated sensitivities of this deformable mirror. Our analyses show that, given the current limited insight concerning the process window of EUV generation, the HPAM module should have an actuator pitch of ≤ 4 mm. Furthermore we have modelled the sensitivity of performance with respect to dimpling and actuator noise. For example, for a deformable mirror with an actuator pitch of 4 mm, and if the associated performance impact is to be limited to smaller than 5%, the actuator noise should be smaller than 45 nm (rms). Our tools assist in the detailed design process by assessing the performance impact of various design choices, including for example those that affect the shape and spectral content of the influence function.

Date Published: 22 February 2017
PDF: 13 pages
Proc. SPIE 10097, High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VI, 1009704 (22 February 2017); doi: 10.1117/12.2249739

Published in SPIE Proceedings Vol. 10097:
High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VI
Stefan Kaierle; Stefan W. Heinemann, Editor(s)