A semiconductor device and a manufacturing method thereof are provided. The semiconductor device has an active surface. The semiconductor device includes at least a connecting element and at least a bump. The connecting element is disposed on the activate surface and has a minimum dimension smaller than 100 microns. The bump is disposed on the connecting element and is electrically connected to the active surface by the connecting element. The bump includes a pillar part disposed on the connecting element and a top part disposed at the top of the pillar part. The pillar part has a first dimension and a second dimension both parallel to the active surface. The first dimension is longer than 1.2 times the second dimension. The top part is composed of solder and will melt under the determined temperature. The pillar part will not melt under a determined temperature.