Porous alumina as low-epsilon insulator for multilevel metallization

Electrochemical anodizing technique was used to form an interlevel alumina insulator for multilevel aluminum metallization. The low dielectric constan t of about 2.4 was reached by chemical etching of porous alumina films in a nodizing solution. The interlevel insulator based on porous alumina had the following parameters measured: the breakdown voltage was more than 400 V, the leakage current at 15 V applied voltage was less than 10(-9) A/cm(2). T he developed processing technique was tested for CMOS submicron technology. The fabricated aluminum-porous alumina structure demonstrated a good chemi cal and thermal stability, excellent adhesion to underlying and top layers. (C) 2000 Elsevier Science B.V. All rights reserved.