Wet etching 0604102-218
An etching process in liquid phase by reactive chemical solution.
To apply wet etching, the region to be left unetched is covered
with a mask in advance whereas the rest is left exposed, then the material is dipped into the
reactive solution. Etching processes are classified into the isotropic etching that is independent
of the crystalline structure of the material, and the anisotropic etching that is dependent on it.
In an isotropic etching process, corrosion progresses in all directions at a uniform speed from an
unmasked region on the surface resulting a round-shape cross section. On the other hand, in an
anisotropic etching process, the etching rate varies at different crystalline directions of the
material, leaving the plane of the slowest etching rate unetched that determines the final shape.