Ablation depth in planar Sn targets during the interaction with a Nd:YAG laser for extreme ultraviolet lithography

Russell A. Burdt; Sam Yuspeh; Kevin L. Sequoia; Mark S. Tillack; Yezheng Tao; Farrokh Najmabadi

doi:10.1117/12.814233

18 March 2009 Ablation depth in planar Sn targets during the interaction with a Nd:YAG laser for extreme ultraviolet lithography

Russell A. Burdt, Sam Yuspeh, Kevin L. Sequoia, Mark S. Tillack, Yezheng Tao, Farrokh Najmabadi

Author Affiliations +

Proceedings Volume 7271, Alternative Lithographic Technologies; 72712Z (2009) https://doi.org/10.1117/12.814233
Event: SPIE Advanced Lithography, 2009, San Jose, California, United States

Abstract

The depth of mass ablation in planar Sn targets during the interaction with a pulsed Nd:YAG laser was investigated. The pulse duration and laser spot size were fixed, and the laser energy was varied to achieve laser intensities from approximately 10¹¹ to 10¹² W/cm², which is relevant to the extreme ultraviolet (EUV) lithography application. The ablation depth was measured by irradiating layered targets consisting of a thin Sn coating with variable thickness evaporated onto a Si wafer. The Sn coating thickness at which the signatures of Si ions in the expanding plasma disappeared indicated the ablation depth. Redundant diagnostics were utilized to detect Si ions in the expanding plasma, including a calibrated EUV energy monitor, an EUV spectrometer, and an electrostatic ion energy analyzer. The ablation depth was found to scale with the laser intensity to the (5/9)^th power, which is consistent with analytical models of steady-state laser ablation developed for the laser fusion application, at which laser intensity is generally higher than present in the EUV lithography application.

Citation Download Citation

Russell A. Burdt, Sam Yuspeh, Kevin L. Sequoia, Mark S. Tillack, Yezheng Tao, and Farrokh Najmabadi "Ablation depth in planar Sn targets during the interaction with a Nd:YAG laser for extreme ultraviolet lithography", Proc. SPIE 7271, Alternative Lithographic Technologies, 72712Z (18 March 2009); https://doi.org/10.1117/12.814233

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available