A fabrication method of an electronic device is provided. First, a substrate is provided. Then, a patterned amorphous carbon (α-C) layer is formed on the substrate and exposes part of the substrate. Next, a first α-C layer covering the patterned α-C layer and part of the substrate is formed. Then, part of the substrate and part of the first α-C layer covering part of the substrate are removed, so as to form a patterned substrate and a second α-C layer.