A semiconductor package includes a lower semiconductor chip, a first upper semiconductor chip including upper pads, and bonding wires coupled to the substrate and the upper pads. The first upper semiconductor chip has a first overhang region adjacent to a first lateral surface of the first upper semiconductor chip, a second overhang region adjacent to a second lateral surface of the first upper semiconductor chip, and a first corner overhang region adjacent to a corner where the first and second lateral surfaces meet with each other. The upper pads include first upper pads on the first overhang region and second upper pads on the second overhang region. The number of the first upper pads is less than that of the second upper pads. The upper pads are spaced apart from the first corner overhang region.

A method for fabricating a semiconductor package may include: providing a first stack including a first pad; forming a lower bump including a first metal on the first pad; forming an upper bump including a second metal different from the first metal on the lower bump, wherein a Young's modulus of the second metal is lower than a Young's modulus of the first metal, and a melting point of the second metal is 400 degrees Celsius or higher; providing a second stack including a second pad, wherein the second pad includes a concave inner face defining an insertion recess; and bonding the first stack and the second stack by inserting the upper bump into the insertion recess of the second pad.

A semiconductor package includes a package substrate having a first side portion adjacent to a first edge, and a second side portion adjacent to a second edge opposite the first edge; a plurality of first substrate pads on the package substrate at the first side portion of the package substrate; a first chip on the package substrate; a second chip stacked on the first chip in a step-wise manner to result in a first exposure region exposing a portion of a surface of the first chip with respect to the second chip due to the step-wise stacking, the first exposure region being adjacent to a first edge of the first chip; a plurality of first bonding pads on a first portion of the first exposure region, the first portion of the first exposure region being adjacent to the first edge of the first chip; a plurality of second bonding pads on a second portion of the first exposure region, the second portion of the first exposure region further from the first edge of the first chip than the first portion of the first exposure region is to the first edge of the first chip, the plurality of second bonding pads being electrically insulated from any circuit components in the first chip; a plurality of third bonding pads on a surface of the second chip; and a plurality of bonding wires electrically connecting the third bonding pads to the first substrate pads via the second bonding pads.