Investigation of surface and mechanical properties of Anodic Aluminium Oxide (AAO) developed on Al substrate for an electronic package enclosure

Semiconductor electronic devices are generally covered with a protective enclosure to surround the internal components and protect them from adverse conditions. These enclosures are developed based on different fabrication methods to form a final product in a single sheet preferably made of aluminium alloys. In this study, Anodic Aluminium Oxide-nanopore (AAO-np) structure was developed on aluminium alloy using a two-step anodization process and the performance of AAO-np was investigated as an enclosure coating material for electronic packaging. The surface and mechanical characteristics of AAO-np has been studied via field emission scanning electron microscopy (FESEM), contact angle measurements, surface roughness profilometry, Vickers hardness and scratch tester. The results were compared and discussed with commercially available surface modified coatings such as anodized, sandblast and other opaque layer coatings on aluminium alloy surfaces. Each step of the AAO-np template formation was observed and the resulting template has 40 to 55 nm pore diameter and 6 to 7 mu m layer thickness. Electrochemically developed AAO-np enclosure was obtained with 63 degrees contact angle and 46 mJ/m(2) surface energy with improved wettability condition on its internal surface. The coating exhibited roughness of 0.73 mu m, indentation hardness of 1333 MPa and scratch hardness of 882 MPa on the external surface. Results show an enhanced property of AAO-np coating as a feasible option for the electronic package enclosures.