A semiconductor device with high heat dissipation efficiency includes a base structure, a semiconductor chip, a heat dissipating structure, and a package body. The semiconductor chip is disposed on the base structure and has a first surface distant from the base structure. The heat dissipating structure includes a buffer layer and a first heat spreader. The buffer layer is disposed on the first surface of the semiconductor chip and a coverage rate thereof on the first surface is at least 10%. The first heat spreader is disposed on the buffer layer and bonded to the first surface of the semiconductor chip through the buffer layer. The package body encloses the semiconductor chip and the heat dissipating structure, and the package body and the buffer layer have the same heat curing temperature.