Provided are a semiconductor device and a bonding structure thereof, in which an inter-metal compound is not formed with a semiconductor die or a lead frame, thereby improving electrical and mechanical properties and wettability and suppressing conglomeration of a die bonding material. The semiconductor device includes a semiconductor die, a barrier layer formed on a surface of the semiconductor die, a first metal layer formed on the barrier layer, a central metal layer formed on the first metal layer, and a second metal layer formed on the central metal layer. Here, the first and second metal layers have a first melting temperature, and the central metal layer has a second melting temperature lower than the first melting temperature.