18 December 1998 EUV mask absorber defect repair with focused ion beam
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In this paper, the Extreme Ultra Violet (EUV) mask absorber repair using focused ion beam (FIB) is investigated. It is well known that focused ion beam repair for the opaque defect removal can easily cause both damage and gallium staining or contamination to the substrate. The damage and gallium staining will induce a localized transmission loss in the case of conventional transmission optical mask. The situation become even worse in the case of reflective EUV mask since gallium is very absorbent at EUV wavelength of 13.4 nm. In addition, the incident beam travels double path through the damaged region due to the reflective nature of the mask. To minimize or even eliminate the repair induced damage, we designed a mask flow to incorporate a SiO2 sacrificial layer beneath the metal absorber layer. This sacrificial layer will become a buffer layer for the metal defect repair. The repair, therefore, will only result in the damage on the sacrificial SiO2 layer instead of EUV reflective multilayer (ML). After the repair, the damaged and contaminated SiO2 layer will be etched away by either wet or dry etch. In the study, we performed both high voltage of 30 kv repair and low voltage of 10 kv repair. We found that in addition to use a sacrifice layer, low voltage focused ion beam repair is also necessary to ensure the damage and contamination free ML substrate.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Pei-yang Yan, Pei-yang Yan, Souping Yan, Souping Yan, Guojing Zhang, Guojing Zhang, Patrick A. Kearney, Patrick A. Kearney, John D. Richards, John D. Richards, Patrick Kofron, Patrick Kofron, Jenn Chow, Jenn Chow, } "EUV mask absorber defect repair with focused ion beam", Proc. SPIE 3546, 18th Annual BACUS Symposium on Photomask Technology and Management, (18 December 1998); doi: 10.1117/12.332828; https://doi.org/10.1117/12.332828


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