A method includes forming a first sealing layer at a first edge region of a first wafer; and bonding the first wafer to a second wafer to form a wafer stack. At a time after the bonding, the first sealing layer is between the first edge region of the first wafer and a second edge region of the second wafer, with the first edge region and the second edge region comprising bevels. An edge trimming process is then performed on the wafer stack. After the edge trimming process, the second edge region of the second wafer is at least partially removed, and a portion of the first sealing layer is left as a part of the wafer stack. An interconnect structure is formed as a part of the second wafer. The interconnect structure includes redistribution lines electrically connected to integrated circuit devices in the second wafer.

A semiconductor package includes a package substrate including a plurality of bonding pads, a plurality of semiconductor chips mounted on an upper surface of the package substrate, and each including a plurality of pads, the plurality of pads including a power voltage pad, a ground voltage pad, and a first signal pad and a second signal pad adjacent to each other, a plurality of connection lines including a first signal line connecting the first signal pads to the first bonding pad, and a second signal line connecting the second signal pads to the second bonding pad, and a first dummy line disposed between the first signal line and the second signal line.

A semiconductor device has a semiconductor substrate and first insulating layer formed over the surface of the semiconductor substrate. A dummy via is formed through the first insulating layer. A second insulating layer is formed over the first insulating layer to fill the dummy via. A first conductive layer is formed over the second insulating layer. A bump is formed over the first conductive layer adjacent to the dummy via filled with the second insulating layer. A second conductive layer is formed over a surface of the semiconductor substrate. The dummy via filled with the second insulating layer relieves stress on the second conductive layer. A plurality of dummy vias filled with the second insulating layer can be formed within a designated via formation area. A plurality of dummy vias filled with the second insulating layer can be formed in a pattern.