Electrolytic Etchant Regeneration
How fast the etching ratc is being reduced according
to the dissolved metal quantity is demonstrated in fig.,..l.
Regardless of the initial molarity of the FeCl3 etchant the
etching rate goes down by about 1.5 um/min per 10 g/l
of the dissolved metal A higher initial molarity is thus
not equivalent to a more voluminous ~etching·reserve~.
Thus, the use of ferric chloride as etch solution without
any regeneration is problematic most of all regarding
the following two points:
1.: -the permanendy decreasing FcCl3 concentration
of the etch solution due to the change to FeCl2
during the etching process,
2. : -the comparatively low metal absorption of about
30 g/l in relation to a 3.8 molar FeCl3 so1ution.
A.Visser and M. Junker, University of Bremen