A semiconductor package includes a packaging substrate having a first surface and a second surface opposite to the first surface; and a semiconductor die assembled on the first surface of the packaging substrate. The semiconductor die includes a plurality of first bump pads and second bump pads on an active surface of the semiconductor die, a plurality of first copper pillars on the first bump pads, and a plurality of second copper pillars on the second bump pads. The first copper pillars have a diameter that is smaller than that of the second copper pillars.