Chemical etching is done using [[Aluminum Etch]]. You can find etch rates for aluminum from ["Etch rates for micromachining processing"] and ["Etch rates for micromachining processing-Part II"].
==References==
*'''Etch rates for micromachining processing''' https://ieeexplore.ieee.org/abstract/document/546406
*'''Etch rates for micromachining processing-Part II''' https://ieeexplore.ieee.org/abstract/document/1257354