Curtaining Effect in FIB-EM Sample Preparation
- Practical Electron Microscopy and Database -
- An Online Book -

http://www.globalsino.com/EM/  



 

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.

 

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One important issue of EM specimen preparation using FIB is known as the curtaining effect. This effect presents the formation of striations across the milling face when the sample has a surface with uneven topography and structures or chemical composition [1 - 2]. This effect often gives trouble to the microelectronics industry because the device structures exist at wafer surfaces. The curtaining artifact occurs when the FIB-sputtering rates are different at different locations (e.g. a tungsten contact to silicon [4]) or voids presents within the specimen.

An immediate consequence of the curtain effect related to TEM specimen is that the specimen will no longer have a uniform thickness. To avoid this issue, bottom and side cleaning procedures had been proposed [1, 3].

To eliminate the curtaining artifacts, one can mill the sample from the sides or bottom [5,6]. On the other hand, obtaining high quality thin TEM-specimen, free from damage, requires low-kV milling. However, the curtaining artifacts can be worse at low kV if it occurs.

 

[1] Langford RM. 2006. Focused ion beams techniques for nanomaterials characterization. Microsc Res Tech 69:538–549.
[2] Ishitani T, Umemura K, Ohnishi T, Yaguchi T, Kamino T. 2004. Improvements in performance of focused ion beam cross sectioning:
aspects of ion-sample interaction. J Electron Microsc 53:443–449.
[3] Wang Z, Kato T, Hirayama T, Kato N, Sasaki K, Saka H. 2005. Surface damage induced by focused-ion-beam milling in a Si/Si p-n junction cross-sectional specimen. Appl Surf Sci 241:80–86.
[4] Introduction to Focused Ion Beams, eds. L.A. Giannuzzi and F.A. Stevie, Springer (2005).
[5] Eduardo Montoya et al. Microscopy Research and Technique 6 (2007) 70 1060.
[6] Stephen M. Schwarz1 et al., Microsc. Microanal. 9 (Suppl. 2) (2003) 116.

 

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