A manufacturing method according to an embodiment of the present invention includes: a step of forming a tapered first groove on a surface of a semiconductor wafer; a step of forming a notch groove having a narrow width in a bottom portion of the first groove; a step of laminating the semiconductor wafer to a mother glass substrate using a sealing material; a step of forming a tapered second groove on a back surface of the semiconductor wafer; a step of separating a semiconductor substrate of the semiconductor wafer by cutting the semiconductor wafer from the second groove toward the notch groove; and a step of separating respective counter substrates by cutting the mother glass substrate along a scribe groove.