A method includes encapsulating a plurality of package components in an encapsulant, and forming a first plurality of redistribution layers over and electrically coupling to the plurality of package components. The first plurality of redistribution layers have a plurality of power/ground pad stacks, with each of the plurality of power/ground pad stacks having a pad in each of the first plurality of redistribution layers. The plurality of power/ground pad stacks include a plurality of power pad stacks, and a plurality of ground pad stacks. At least one second redistribution layer is formed over the first plurality of redistribution layers. The second redistribution layer(s) include power lines and electrical grounding lines electrically connecting to the plurality of power/ground pad stacks.