A chip package includes a first integrated-circuit (IC) chip; a second integrated-circuit (IC) chip over the first integrated-circuit (IC) chip; a connector over the first integrated-circuit (IC) chip and on a same horizontal level as the second integrated-circuit (IC) chip, wherein the connector comprises a substrate over the first integrated-circuit (IC) chip and a plurality of through vias vertically extending through the substrate of the connector; a polymer layer over the first integrated-circuit (IC) chip, wherein the polymer layer has a portion between the second integrated-circuit (IC) chip and connector, wherein the polymer layer has a top surface coplanar with a top surface of the second integrated-circuit (IC) chip, a top surface of the substrate of the connector and a top surface of each of the plurality of through vias; and an interconnection scheme on the top surface of the polymer layer, the top surface of the second integrated-circuit (IC) chip, the top surface of the connector and the top surface of each of the plurality of through vias.