In this work factors affecting the anisotropy (i.e., difference in vertical and lateral anodization rates) of the aluminum anodization process are investigated. By varying the electrochemical process parameters, a degree of anisotropy of about 0.6 was obtained. The structure of the aluminum porous oxide was determined by a Scanning Electron Microscope. The difference in the anodization conditions for porous aluminum oxide growth along lateral and vertical direction was determined. The developed processing technique was used for forming multilevel VLSI metallization with feature sizes of about 1.2 µm.