A manufacturing method of a semiconductor device includes the following steps. First patterned structures are formed on a substrate. Each of the first patterned structures includes a first semiconductor pattern and a first bottom protection pattern disposed between the first semiconductor pattern and the substrate. A first protection layer is formed on the first patterned structures and the substrate. A part of the first protection layer is located between the first patterned structures. A first opening is formed in the first protection layer between the first patterned structures. The first opening penetrates the first protection layer and exposes a part of the substrate. A first etching process is performed after forming the first opening. A part of the substrate under the first patterned structures is removed by the first etching process for suspending at least a part of each of the first patterned structures above the substrate.