Im not sure what exactly you want to lap (which kind of material), but we are using Chemlox Polishing Fluid (bought by Logitech) for lapping GaAs-wafers. But it's written you can lap silicon and lots of electro-optical devices ...

http://www.logitech.uk.com/products-solutions/products-and-accessories/consumables/polishing-suspensions.aspx#!prettyPhoto

hmm we save our structures with crytsalbond wax, because we have to remove it after lapping. Its melting at 50-70 °C and can be removed in aceton easily.

http://www.emsdiasum.com/microscopy/products/materials/adhesives.aspx

Since we lapp for a completely different reason I don't think I can answer your question. This is really up to you, how thin you can or have to go.

its OK, if due to some constraints its not possible to answer. Thanks anyway for the answers

I can tell you how far we lapp, but as I said it's for different purpose. So we lapp our wafers to some 10 µm (to reduce some etching times).

Dear Gul,

There is the mechanical lapping after sawing the wafers to remove the waves of the sawing. For silicon one uses normally mechanical lapping using abrasives from fine silicon carbides and lapping machines.

To get polished mirror like surfaces after lapping and preserving very flat surfaces one uses chemical mechanical polishing with a mixture of very fine alumina powder + Potassiumhydroxide which has a commertial name for silicon CMP.

Best wishes