A manufacturing method of a semiconductor device is provided to manufacture an increased number of semiconductor devices per single substrate such as, e.g., a wafer while obviating damages like those caused by conventional dicing method. The manufacturing method comprises steps of performing a first etching process to etch a separation area on a front surface of a substrate, arranging a supporter on a back surface of the first substrate to prevent semiconductor devices from coming apart, coating with a thin film a non-etching area including a sidewall of the etched separation area and excluding a bottom of the etched separation area on the front surface of the first substrate, and performing a second etching process to etch the first substrate from the front surface through an area not coated by the thin film to divide the substrate into multiple semiconductor devices.