A package includes a die, which includes a semiconductor substrate, a plurality of through-vias penetrating through the semiconductor substrate, a seal ring overlapping and connected to the plurality of through-vias, and a plurality of electrical connectors underlying the semiconductor substrate and connected to the seal ring. An interposer is underlying and bonded to the die. The interposer includes a substrate, and a plurality of metal lines over the substrate. The plurality of metal lines is electrically coupled to the plurality of electrical connectors. Each of the plurality metal lines has a first portion overlapped by the first die, and a second portion misaligned with the die. A heat spreader encircles the die and the interposer. A wire includes a first end bonded to one of the plurality of metal lines, and a second end bonded to the heat spreader.