Semiconductor package including step seal ring and methods forming same

Abstract

A method includes forming a plurality of dielectric layers over a semiconductor substrate, forming a plurality of metal lines and vias in the plurality of dielectric layers, forming a lower portion of an inner seal ring and a lower portion of an outer seal ring extending into the plurality of dielectric layers, depositing a first dielectric layer over the plurality of metal lines and vias, and etching the first dielectric layer to form an opening penetrating through the first dielectric layer. After the first dielectric layer is etched, a top surface of the lower portion of the inner seal ring is exposed, and an entire topmost surface of the lower portion of the outer seal ring is in contact with a bottom surface of the first dielectric layer. An upper portion of the inner seal ring is then formed to extend into the opening and to join the lower portion of the inner seal ring. A second dielectric layer is deposited to cover the upper portion of the inner seal ring.