Wafer

A wafer comprising:

• a substrate layer having a first surface and a second surface opposite to the first surface;
• a first mirror layer having a plurality of first mirror portions two-dimensionally arranged on the first surface;
• and
• a second mirror layer having a plurality of second mirror portions two-dimensionally arranged on the first mirror layer,
• wherein a plurality of Fabry-Perot interference filter portions are formed in an effective area, in each of the plurality of Fabry-Perot interference filter portions a gap is formed between the first mirror portion and the second mirror portion facing each other and a distance between the first mirror portion and the second mirror portion facing each other varies by an electrostatic force,
• a plurality of dummy filter portions are formed in a dummy area disposed along an outer edge of the substrate layer and surrounding the effective area, in each of the plurality of dummy filter portions an intermediate layer is provided between the first mirror portion and the second mirror portion facing each other, and
• at least the second mirror portion is surrounded by a first groove opening on a side opposite to the substrate layer in each of the plurality of Fabry-Perot interference filter portions and the plurality of dummy filter portions.