A power semiconductor is provided. The power semiconductor includes a gate, a source, a silicon chip and a drain. The source includes a first copper particle layer and a first metal layer. The first copper particle layer covers the upper surface of the first metal layer. The silicon chip is bonded to the lower surface of the first metal layer. The drain is bonded to the lower surface of the silicon chip. The thickness of the first copper particle layer is greater than the thickness of the first metal layer. All copper mentioned are of large grain copper with size greater than 0.25 um.