A nitride semiconductor device includes a semiconductor carrier, a first nitride-based chip, and first conformal connecting structures. The first nitride-based chip is disposed over the semiconductor carrier. The semiconductor carrier has a first planar surface. The first nitride-based chip has a second planar surface, first conductive pads, and first slanted surfaces. The first conductive pads are disposed in the second planar surface. The first slanted surfaces connect the second planar surface to the first planar surface. The first conformal connecting structures are disposed on the first planar surface and the first nitride-based chip. First obtuse angles are formed between the second planar surface and the first slanted surfaces. Each of the first conformal connecting structures covers one of the first slanted surfaces of the first nitride-based chip and one of the first obtuse angles and is electrically connected to the first conductive pads.