Abstract: In order to provide a technique capable of executing an etching process using a dry etching method and a wet etching method in combination with high processing dimensional accuracy, an interlayer insulating film 13, an etching stopper film 14, interlayer insulating films 15 and 18 and a surface protection film 19 are sequentially deposited on a sensor film 12. As the etching stopper film 14, a material different in etching selectivity from the interlayer insulating films 13, 15 and 18 is selected. Next, the surface protection film 19 and the interlayer insulating films 18 and 15 are sequentially dry-etched with using the etching stopper film 14 as an etching stopper, and subsequently, the etching stopper film 14 is dry-etched with using the interlayer insulating film 13 as an etching stopper. Thereafter, the interlayer insulating film 13 is wet-etched with using the sensor film 12 as an etching stopper.