Nanofabrication at Harvard CNS : E-beam resist – Ep3

May 18, 2018 By sky Leave a Comment

Summary

The main criteria for choosing the appropriate resist depend on the minimum feature size, sensitivity, contrast and etching resistance. There is a large number of parameters affecting the EBL process in a complex, interacting fashion. Therefore, a better understanding on the complexity of these interactions can lead to a succcessful EBL

comparison of etch resistance between ZEP520 and PMMA — P1
Four main properties to characterize E-beam resists

how to measure E-beam resist contrast — P2
Contrast(γ) describes how abrupt is the dependence of thickness on dose

E-beam resist sensitivity and writing speed — P3
The higher sensitivity of E-beam resist indicates that the clearance dose is reduced. Therefore, using a more sensitive E-beam resist is a benefit in terms of improving resolution and writing speed

Writing speed and parameters to affect performance of E-beam resists — P4
Using high beam current in EBL limits the minimum feature size due to the space charge blowup but ensures the fast writing speed. Using lower beam current ensures higher resolution but results in slow writing speed.

using higer sensitivity of E-beam resist helps EVL to improve the writing speed — P5
For a fixed beam current using E-beam resist with higher sensitivity improves the writing speed

Select a E-beam ressit suitable for your process and requirement — P6
Suucessful EBL requires understanding about E-beam characteristics and parameters affecting EBL performance. Understanding your process and requirements is required to select a E-beam resist suitable for your application.

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Ep1
Ep2
Ep3

Reference

A E Grigorescu and C W Hagen, Delft University of Technology. “Resists for sub-20-nm electron beam lithography with a focus on HSQ: state of the art.” Nanotechnology 20 (2009)
Bo Cui, ECE, University of Waterloo; http://ece.uwaterloo.ca/~bcui/, "The electron beam lithography-2"
Mohammad M.A., Muhammad M., Dew S.K., Stepanova M. (2012) Fundamentals of Electron Beam Exposure and Development. In: Stepanova M., Dew S. (eds) Nanofabrication. Springer, Vienna
Nicole Devlin, et al. Georgia Technology. “Dose Determination Using ZEP520A Resist as a Model.”
Georgia Technology. A comparison of electron beam lithography resists PMMA and ZEP520A.”
Zeon Corporation. ZEP520A Technical report.”
Martin M. Greve, Bodil Holst. 2013. “Optimization of an electron beam lithography instrument for fast, large area writing at 10 kV acceleration voltage.” Journal of Vacuum Science & Technology B 31, 043202
Roberto Fallica, et al. Paul Scherrer Institute. “Lithographic performance of ZEP520A and mr-PosEBR resists exposed by electron beam and extreme ultraviolet lithography.” Journal of Vacuum Science & Technology B 35, 061603 (2017)

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