Submicron Sidewall Fabrication Utilizing Aluminum Anodization
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
This article describes a process which consists of anodizing aluminum to form an Al2O3 sidewall for the production of submicron features in integrated circuit manufacturing. A blanket of aluminum is deposited over a thin layer of SiO2 (Fig. 1). A layer of low temperature, CVD (chemical vapor deposition) SiO2 is deposited over the aluminum. A mask is used to pattern the SiO2 and aluminum. The resist is left on to prevent anodization of the aluminum through pin holes in the CVD SiO2 . The wafer is placed in a bath of oxalic acid solution or a solution of NH3OH. A voltage is applied to the wafer, and Al2O3 is formed on the exposed aluminum sidewall (Fig. 2). The applied potential controls the thickness (lateral dimension) of the Al2O3. Removal of the resist, aluminum, and CVD SiO2 leaves a free-standing Al2O3 stud (Fig. 3).