In recent years, as electronic equipment becomes thinner, an area for mounting a semiconductor device used in the electronic equipment is required to be smaller, and a thickness of an encapsulating resin for encapsulating a semiconductor substrate having a circuit formed thereon and the like also becomes smaller. The encapsulating resin is marked with a product number, a manufacturer name, or the like. There arises a problem in that, in the marking, an infrared laser beam applied to the encapsulating resin passes through the encapsulating resin, generates heat in the semiconductor substrate, and destructs the formed circuit. By providing a thin film for refracting the infrared laser beam on a rear surface of the semiconductor substrate, the optical path of the infrared laser beam is made longer to reduce heat generated in the semiconductor substrate.