I am trying to glue a colloidal tip on a gold coated AFM cantilever. When the location of tip is not the one I want, I need to wash out the glue with an organic solvent and try another particle. probably since Ethanol oxidizes the gold (?) I noticed that the gold covered side of cantilever goes bad when I use Ethanol for cleaning. I am looking for a solvent that does not have any effect on either cantilever or its coating (Al or Au). I appreciate comments and suggestions.
Dear Behzad Vaziri,
I can suggest Toluene (https://en.wikipedia.org/wiki/Toluene). In our work we use this solvent to remove organic contamination or wax mask from a silicon surface with Al contact pads. Al contact were not damaged during the cleaning procedure.
On the other hand, we also have used Ethanol for cleaning and there were now problem. Ethanol should not oxidized gold, may be the ethanol was not clean enough or gold had a bad adhesion to the cantilever surface.
Can you use a combination of Acetone and Isopropanol (IPA) cleaning, as used in standard lithography cleaning steps? Acetone and IPA will not react with Au, which I know from personal experience. As such, pure ethanol shouldn't either. However, if your tip assembly has any plastic/polymer material, then Acetone will degrade it. In that case, just use IPA.
We use Ethanol or Acetone with sonification for cleaning cantilevers (it is necessary to be very careful - it can be destroyed!). In some cases we use Piranha solution for strong cleaning. In all cases we do not have any problem with the mirror side of a cantilever.
It is impossible to oxidize a gold layer by Ethanol. Probably your solvent is contaminated and you have a film on the mirror surface after drying. Just change Ethanol or still it :)
If the mirror layer is damaged it is not serious problem: you can make new thin (about 10 nm) gold layer by conventional coater for SEM samples, I have done it many times.
Good luck!
Xylene may be a suitable solvent to clean some types of adhesive residues. However, due to its relatively high toxicity, we may want to avoid xylene use, at least when safer alternatives can be considered. Moreover, xylene may possibly leave a residue stain after drying, which may require another solvent (e.g. isopropyl alcohol: IPA) to be cleaned. A binary solvent mixture obtained by adding ~85 vol% of either petroleum ether, pentane, n-hexane, or ligroin; to IPA (~15 vol%) may be alternatively considered. The secondary solvent (IPA) helps to avoid possible drying stains that otherwise could be leaved by insoluble residue. This solvent mixture was earlier suggested at this forum as a suitable cleaner for a type of 'immersion oil': https://www.researchgate.net/post/How_do_I_clean_Cargille_type_A_immersion_oil_from_a_NBK-7_glass_slide_coated_in_a_200_nm_MgF2_film
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