A semiconductor device package includes a first substrate, a dielectric layer, a thin film transistor (TFT) and an electronic component. The first substrate has a first surface and a second surface opposite to the first surface. The dielectric layer is disposed on the first surface of the first substrate. The dielectric layer has a first surface facing away from the first substrate and a second surface opposite to the first surface. The TFT layer is disposed on the dielectric layer. The electronic component is disposed on the second surface of the first substrate. A roughness of the first surface of the dielectric layer is less than a roughness of the first surface of the first substrate.