A method of fabricating a stacked dielectric layer for suppressing electrostatic charge buildup. First, a substrate having metal layers thereon is provided, with a plurality of gaps formed therebetween. Next, a dielectric layer is formed by simultaneous deposition and ion-bombardment, such that the dielectric layer covers the bottom dielectric liner and fills the gaps. Finally, a top dielectric liner is formed on the dielectric layer by deposition without ion-bombardment. Furthermore, the present invention provides another method to fabricate a stacked dielectric layer by performing a plasma treatment on the dielectric layer to suppress electrostatic charge buildup. As a result, the above-mentioned methods can efficiently avoid metal extrusion issues.