Seal Ring Structure with Zigzag Patterns and Method Forming Same

A method includes forming a plurality of dielectric layers, forming a lower portion of a seal ring including a plurality of metal layers, each extending into one of the plurality of dielectric layers, depositing a first passivation layer over the plurality of dielectric layers, forming an opening in the first passivation layer, forming a via ring in the opening and physically contacting the lower portion of the seal ring, and forming a metal ring over the first passivation layer and joined to the via ring. The via ring and the metal ring form an upper portion of the seal ring. The metal ring includes an edge portion having a zigzag pattern. The method further includes forming a second passivation layer on the metal ring, and performing a singulation process to form a device die, with the seal ring being proximate edges of the device die.