Package structures and methods for manufacturing the same are provided. The package structure includes a first bump structure formed over a first substrate. The first bump structure includes a first pillar layer formed over the first substrate and a first barrier layer formed over the first pillar layer. In addition, the first barrier layer has a first protruding portion laterally extending outside a first edge of the first pillar layer. The package structure further includes a second bump structure bonded to the first bump structure through a solder joint. In addition, the second bump structure includes a second pillar layer formed over a second substrate and a second barrier layer formed over the second pillar layer. The first protruding portion of the first barrier layer is spaced apart from the solder joint.