The present application discloses a method for fabricating a semiconductor device. The method includes providing a first chip comprising a first substrate, a first redistribution layer positioned above the first substrate, a first lower bonding pad positioned on the first redistribution layer, and a second lower bonding pad positioned above the first substrate and distant from the first lower bonding pad. The method also includes providing a second chip comprising a dense region and a loose region adjacent to the dense region; a plurality of upper pads positioned on the first lower bonding pad and the second lower bonding pad; and a plurality of second redistribution layers positioned on the plurality of upper pads. The method further performs bonding the second chip onto the first chip in a face-to-face manner, wherein the plurality of upper pads contact the first lower bonding pad and the second lower bonding pad.