Chip packages and methods for forming the same are provided. The chip package includes a substrate having a stepped sidewall, a first surface, and a second surface. The first surface and the second surface are opposite each other. The first surface and the second surface adjoin the stepped sidewall. The chip package also includes a capping layer having a first surface and a second surface opposite each other. The first surface of the capping layer faces the second surface of the substrate. The chip package further includes a dam structure and an adhesive layer. The dam structure bonds the capping layer to the substrate, and surrounds a sensing region in the substrate. The adhesive layer surrounds the dam structure and has a concave-tapered sidewall that extends along the outer edge of the dam structure in the direction from the second surface of the substrate to the capping layer.