Translator Disclaimer
1 April 2013 Through-focus EUV multilayer defect repair with nanomachining
Author Affiliations +
Defects within the multilayer mirrors of EUV photomasks have been a leading challenge for EUV lithography for quite some time. By creating non-planar surfaces, they distort both the amplitude and phase of reflected light. Amplitude errors generally create a CD error on wafer, whereas phase errors tend to cause asymmetric printing through focus. Since defect-free mask blanks are not expected to be available for initial high volume EUV manufacturing, defect mitigation, compensation, and repair strategies are essential. This paper describes a technique to repair both the amplitude and phase effects of multilayer defects. For a bump defect, the phase effect (i.e. tilted Bossung curve behavior) is corrected by removing multilayer material in the vicinity of the defect. This creates a phase effect opposite to that of the defect and the two effects cancel. The amplitude error (i.e. CD error) caused by both the defect and by the phase repair is then corrected by modifying the surrounding absorber pattern. The repairs in this paper are performed by nanomachining with an AFM repair tool. The concept is validated by a combination of simulation and experimental studies with data from the Actinic Inspection Tool (AIT) at the Lawrence Berkeley National Laboratories, the EUV Alpha Demo Tool (ADT) in Albany, New York, and an AFM repair tool. The process for a complete multilayer repair is described using an example native defect repair. Encouraging results indicate that nanomachining is capable of creating the complex nano-scale three dimensional topographies required for the repair. Repair strategies for both bump and pit defects are addressed. Multiple simulation studies are used to understand the requirements for such a repair and what type of repairs may be possible.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gregory McIntyre, Emily Gallagher, Tod Robinson, Adam C. Smith, Mark Lawliss, Jeffrey LeClaire, Ron Bozak, Roy White, and Michael Archuletta "Through-focus EUV multilayer defect repair with nanomachining", Proc. SPIE 8679, Extreme Ultraviolet (EUV) Lithography IV, 86791I (1 April 2013);


Defect printability studies at SEMATECH
Proceedings of SPIE (June 28 2013)
EUVL mask repair: expanding options with nanomachining
Proceedings of SPIE (November 08 2012)
Repair of natural EUV reticle defects
Proceedings of SPIE (October 13 2011)
EUV mask infrastructure challenges
Proceedings of SPIE (May 03 2007)

Back to Top