Patent ID: 8162439

Claim:
A method for manufacturing a nozzle plate for a liquid ejection head, wherein a through hole whose one opening is an ejection port ejecting liquid is arranged on one side of a Si substrate by an anisotropic etching process in which etching and side wall protection film formation are alternately repeated in the Si substrate, the method comprising the following steps performed in the following order: forming a hole of an approximately cylindrical shape having a predetermined depth on an other side of the Si substrate from the one side of the substrate; forming a film to be an etching mask on a surface of the one side of the Si substrate whereupon the ejection port is to be formed; forming the etching mask pattern having an opening for forming the through hole by performing photolithography and etching to a film to be the etching mask on the one side of the Si substrate; and performing etching by the anisotropic etching process by satisfying a conditional relationship below so that the through hole has an approximately cylindrical shape having a diameter smaller than a diameter of the approximately cylindrical shape of the hole on the other side of the substrate, until the through hole reaches the hole on the other side of the Si substrate: D≦ 0.1× R where D is a depth of an etching per one cycle, wherein, in the anisotropic etching process, a repeating unit in which etching and side wall protection film formation are alternately repeated is set to be one cycle, and R is a diameter of an opening of the etching mask pattern to form the through hole.