Extreme ultraviolet lithography (EUVL) is considered as the next generation lithography for 32-nm-node or smaller in semiconductor manufacturing. One of the challenges is to protect the EUVL masks against particle contamination, due to the unavailability of conventional pellicles. In this study, the EUVL mask protection schemes of Asbach et al. (2006. Technical note: Concepts for protection of EUVL masks from particle contamination. Journal of Nanoparticle Research, 8, 705-708), who proposed to mount the mask upside-down, have a cover plate with particle trap and apply phoretic forces, were evaluated against top-down aerosol at atmospheric pressure. Experimental evaluation was performed using 150 mm wafers as witness plates, and PSL particles ranging from 125 to 700 nm. For the numerical assessment of the protection schemes against particles between 10 and 3000 nm, a statistical method using a Lagrangian particle tracking simulation tool was employed to calculate the deposition velocity. It was shown that the critical surface could effectively be protected against top-down aerosol.
Bibliographical noteFunding Information:
This research was supported by the Intel Corporation, and their technical and financial support is gratefully acknowledged. The authors would like to thank Dr. Kevin Orvek and Dr. Arun Ramamoorthy for their valuable comments and discussion. The authors also wish to thank the Supercomputing Institute of the University of Minnesota for the technical support.
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- Deposition velocity
- Lagrangian particle tracking
- Mask carrier
- Mask protection