Patent ID: 8133798

Claim:
A method for producing an ink jet head, the method comprising: first oxidizing in which, in an SOI substrate having a first SiO 2 layer between a first Si layer and a second Si layer, the first Si layer being disposed on a surface of the second Si layer, among the first Si layer and the second Si layer, at least the first Si layer is thermally oxidized to form a second SiO 2 layer; forming a nozzle hole by removing a part of the second SiO 2 layer and a part of the first Si layer between the first SiO 2 layer and the second SiO 2 layer, by performing an etching treatment until at least the first SiO 2 layer is exposed; second oxidizing in which a side wall of at least the first Si layer in the formed nozzle hole is thermally oxidized to form an SiO 2 layer; opening the nozzle hole by subjecting the SiO 2 layers in the nozzle hole other than at the side wall to an anisotropic dry etching treatment until at least the second Si layer is exposed; and forming a nozzle by removing the second Si layer.