The present invention provides a thin and bendable semiconductor device utilizing an advantage of a flexible substrate used in the semiconductor device, and a method of manufacturing the semiconductor device. The semiconductor device has at least one surface covered by an insulating layer which serves as a substrate for protection. In the semiconductor device, the insulating layer is formed over a conductive layer serving as an antenna such that the value in the thickness ratio of the insulating layer in a portion not covering the conductive layer to the conductive layer is at least 1.2, and the value in the thickness ratio of the insulating layer formed over the conductive layer to the conductive layer is at least 0.2. Further, not the conductive layer but the insulating layer is exposed in the side face of the semiconductor device, and the insulating layer covers a TFT and the conductive layer. In addition, a substrate covering an element formation layer side is a substrate having a support on its surface is used in the manufacturing process.