Dear Jeffrrey,

My experience is that if the SU-8 cantilever is very thin (say 1.5 µm) then the
cantilevers will stick to the substrate even with a spacing of several microns.
However, making a 4.5 µm thick cantilever will prevent the stiction. I wouldn't
say it's the hydrophobic/hydrophilic properties of the material that has the
biggest effect but rather the capillary forces since you use a wet release
method.

My advice would be to move to a dry release, as for example the method developed
by D. Haefliger; D.Haefliger et al. Microelectronic Engineering, 78-79 (2005)
88-92.

Good luck!
Maria

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Maria Nordström
PostDoc, Nanoprobes Group
MIC - Department of Micro and Nanotechnology
Technical University of Denmark
Denmark