MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE

A manufacturing method of a semiconductor device includes the following steps. A semiconductor structure including a substrate, a gallium nitride layer, semiconductor device units, and a scribe line region is provided. The gallium nitride layer is disposed on a first surface of the substrate. The semiconductor device units and the scribe line region are disposed on the gallium nitride layer. The scribe line region is located between the semiconductor device units. A trench is formed at a second surface of the substrate. The trench is formed corresponding to the scribe line region in a vertical direction. The trench penetrates through at least a part of the substrate in the vertical direction. A metal layer is formed on the substrate after the trench is formed. A cutting process is performed to the semiconductor structure after the metal layer is formed for separating the semiconductor device units from one another.