Development of barrier anodic oxide Al ₂ O ₃ passivations of aluminum alloy surface for LSI/FPD plasma process equipment

Aluminum alloys are key materials for advanced large-scale integration (LSI)/flat panel display (FPD) plasma process equipment to drastically improve the process performance. There exists a severe disadvantage for aluminum-alloy process chambers, however, i.e., very poor anticorrosion capability to halogen gas plasmas. Thus, the authors have developed very advanced Al2 O3 passivation films having a thickness of 0.1-0.4 μm on aluminum-alloy surfaces exhibiting complete anticorrosion resistance for various radicals such as hydrogen radicals H*, oxygen radicals O*, halogen radicals (Cl*, Br*, F*), and simultaneously various ion bombardments by using nonaqueous anodic oxidations. Porous alumite (alumilite) films having a thickness of 50-200 μm have been provided on aluminum-alloy chamber surfaces as anticorrosion films using aqueous anodic oxidations, particularly for reactive ion etching process chambers. But alumite films (Al2 O3 n H2 O) include huge amounts of water molecules, resulting in the generation of water vapors in the process chamber and leading to the degradation of process quality and the generation of too many particles in the process chamber coming from water-molecule-originated gas-phase reactions. ¹ Plasma process performance of LSI/FPD manufacturing is drastically enhanced by introducing a newly developed Al2 O3 passivated aluminum-alloy chamber to overcome all disadvantages of current plasma process equipment.