Inkjet recording head, method for producing same, and semiconductor device

A method for producing an inkjet recording head including a substrate having a first surface and a second surface opposite the first surface, the substrate being provided with an energy-generating element disposed on the first surface, the energy-generating element being configured to generate energy utilized for discharging ink, and the head including a supply port configured to supply ink, the supply port passing from the first surface to the second surface of the substrate, the method comprising:

• preparing the substrate having a through hole to be formed into a supply port, the through hole having openings on the first surface and the second surface, the substrate having a first protective layer disposed on the second surface, the first protective layer having an overhang extending into the region of the opening on the second surface;
• forming a second protective layer so as to continuously cover at least the overhang of the first protective layer and the inner wall of the through hole;
• and
• removing a portion of the second protective layer corresponding to the opening on the first surface.