In order to use an etching solution of less complicated composition for
recovering used wafers, embodiments of the present invention provide a
recovering method, and also provide a kind of wafer, which is used as a
process control wafer or dummy wafer, and fabrication methods. In one
embodiment, a wafer-recovering method comprises providing a first wafer,
wherein the first wafer has a base, a first conductive layer on the base,
and a second conductive layer on the first conductive layer. The method
further comprises removing the first and second conductive layers with an
acidic solution to obtain a second wafer; and washing the second wafer
with a liquid. The second conductive layer is formed on the first
conductive layer in a deposition process, and the first conductive layer
is more easily removed by the acidic solution than the second conductive
layer.