Method for manufacturing perforated substrate, method for manufacturing liquid ejection head, and method for detecting flaw

A method for manufacturing a liquid ejection head comprising a substrate having an energy-generating device on a first surface and a channel-forming member having an orifice and forming a liquid channel with the first surface of the substrate, the substrate having a through-hole extending through the substrate and communicating with the liquid channel, the through-hole serving as a supply hole through which a liquid is supplied from a second surface opposite the first surface of the substrate to the liquid channel, the method comprising:

• forming at least one through-hole extending through a substrate from a first surface to a second surface;
• forming a film on the first surface, a sidewall of the at least one through-hole, and the second surface;
• forming a resist on the first surface;
• patterning the resist such that the resist closes an opening of the at least one through-hole in the first surface;
• etching the film on the first surface using the resist as a mask;
• before the etching, forming an inspection member on the second surface such that the inspection member closes an opening of the at least one through-hole in the second surface;
• and
• at least one of the steps of:
• a) after the etching, determining whether there is a flaw that causes a film patterning defect from a color change in the inspection member, the color change located at the closed opening of the at least one through-hole in the second surface, wherein the inspection member is an adhesive tape that transmits visible light;
• and
• b) determining whether there is a flaw that causes a film patterning defect from a deformation that appears in the inspection member at an atmospheric pressure, the deformation located at the closed opening of the at least one through-hole in the second surface, wherein the openings of the at least one through-hole in the first and second surfaces are closed at a reduced pressure of 1,000 Pa or less, and the inspection member is a deformable adhesive tape comprising an adhesive layer and a step-covering layer, the adhesive layer and the step-covering layer having a total thickness of 20 to 1,000 μm.

A method for detecting a film patterning defect or a flaw that causes a film patterning defect on a substrate having at least one through-hole and having a film on a first surface, a second surface opposite the first surface, and a sidewall of the at least one through-hole when the film on the first surface is patterned by etching using a resist as a mask, the resist being patterned on the first surface such that the resist closes an opening of the at least one through-hole in the first surface, the method comprising:

• before the etching, forming an inspection member on the second surface such that the inspection member closes an opening of the at least one through-hole in the second surface;
• and
• at least one of the steps of:
• a) after the etching, determining whether there is a flaw that causes a film patterning defect from a color change in the inspection member, the color change located at the closed opening of the at least one through-hole in the second surface, wherein the inspection member is an adhesive tape that transmits visible light;
• and
• b) determining whether there is a flaw that causes a film patterning defect from a deformation that appears on the inspection member at an atmospheric pressure, the deformation located at the closed opening of the at least one through-hole in the second surface, wherein the openings of the at least one through-hole in the first and second surfaces are closed at a reduced pressure of 1,000 Pa or less, and the inspection member is a deformable adhesive tape comprising an adhesive layer and a step-covering layer, the adhesive layer and the step-covering layer having a total thickness of 20 to 1,000 μm.