In a continuous in-vacuum process for the manufacture of a film metallized with aluminum, the aluminum layer is exposed to a passivating agent, inline, immediately after deposition and prior to rewinding of the film onto a take-up roller. Passivation is carried out by plasma treatment in an oxidizing atmosphere (oxygen, nitrogen or others). The resulting product exhibits no peel-off problems during unwinding of the take-up roller and greatly improved corrosion resistance.