Porous-type anodization of patterned similar to 10 mu m thick Al-Cu films results in microstructures with alternating regions of Al-Cu and porous Al2O3. The volumetric expansion of porous Al2O3 is minimized by increasing the anodization solution temperature. The fidelity of the mask transfer (10 mu m wide) is compromised by the lateral pore propagation under the anodization mask. The Al-Cu pillars formed after complete dissolution of porous Al2O3 have a trapezoidal shape. The height of pillars is twice (8 mu m) the distance corresponding to the lateral pore propagation (4 mu m). In contrast to wet chemical etching, porous- type anodization of patterned Al-Cu films is not isotropic. (c) 2006 The Electrochemical Society.