Embodiments include a reflowable grid array (RGA) interposer, a semiconductor packaged system, and a method of forming the semiconductor packaged system. The RGA interposer includes a substrate having vias and zones, where the zones have embedded heaters. The heaters may include first traces, second traces, and via filament interconnects. The vias may have a z-height greater than a z-height of the heaters, and each of the zones may have a grid pattern. The RGA interposer may include first and second layers in the substrate, where the first layer includes the first traces, the second layer includes the second traces, and the second layer is over the first layer. The grid pattern may have parallel first traces orthogonal to parallel second traces to form a pattern of squares, where the pattern of squares has the first traces intersect the second traces substantially at right angles.