An aluminum electrode is rf powered before sputter cleaning of wafers to reduce the partial pressure water vapor in an evaporator. Prolonged sputter cleaning times are thereby avoided because regrowth of the aluminum oxide during sputter cleaning is practically nil. Wafers with temperature sensitive resists, for example, with a polyimide or photoresist lift off mask for fabrication of the conductor lines can be sputter cleaned and low via resistance obtained without mask damage. Histograms of the via resistance as a function of the sputter cleaning time in the range from 15 to 60 s are presented for the as-deposited and sintered metallization. The tooling and the process to obtain low via resistance are described. The author believes, that the principle method and electrode design may be useful for similar applications where a low partial pressure water vapor in a vacuum apparatus is required.