Seal rings generally comprise dummy conductive features, such as metal lines and metal vias that are formed in the redistribution structure (e.g., 140′) around the perimeters of each semiconductor package (e.g., 1100A and 1100B). In other words, in a plan view, each of the seal rings has a ring shape (e.g., a rectangle shape) and encircles a respective semiconductor package (e.g., 1100A, 1100B). The metal lines and metal vias of the seal rings may be formed in the same processing steps and using the same material(s) as the conductive lines (see, e.g., 143 in FIG. 4) and the conductive vias (see, e.g., 145 in FIG. 4) of the redistribution structure 140′. For example, the metal lines and metal vias of the seal rings may be formed in the same dielectric layers that the conductive lines and the conductive vias of the redistribution structure 140′ are formed, except that the metal lines and metal vias of the seal rings are electrically isolated. The seals rings are built to protect, e.g., the redistribution structure of the semiconductor packages from cracking and/or delamination during a subsequent dicing process. For example, when the blade of a dicing saw cuts into the dicing region 300 between two neighboring seal rings, cracks in the redistribution structure 140′, which is caused by the blade, may be stopped by the seal rings and damage to the semiconductor packages may be avoided. Similarly, delamination of the redistribution structure 140, which may otherwise occur due to the dicing, may also be stopped or reduced by the seal rings.