Patent ID: 8877433

Claim:
A method of manufacturing a liquid injection head including an ejection orifice having an inclined shape, the method comprising: forming on a substrate, a negative photosensitive resin layer having a first surface on a side opposite to the substrate and a second surface on the substrate side; carrying out first exposure of the negative photosensitive resin layer under a condition where an unexposed portion is formed so that a cross sectional area thereof taken along a plane in parallel with a substrate surface becomes larger from the second surface toward the first surface; carrying out second exposure of the negative photosensitive resin layer under a condition where an unexposed portion is formed so that a cross sectional area thereof taken along a plane in parallel with the substrate surface becomes smaller from the second surface toward the first surface; and forming the ejection orifice by carrying out development after the first exposure and the second exposure, wherein each of the first surface and the second surface has a portion in which a part of the unexposed portion in the first exposure and a part of the unexposed portion in the second exposure overlap and a portion in which a part of the unexposed portion in the first exposure and a part of the unexposed portion in the second exposure do not overlap.