Patent ID: 8881399

Claim:
A manufacturing method of a nozzle plate for a liquid ejection head, the nozzle plate comprising a plate having a through hole which comprises a large diameter portion open into one side of the nozzle plate and a small diameter portion which has a smaller cross section than a cross section of the large diameter portion, the small diameter portion open into an other side surface of the nozzle plate, and in which an aperture of the small diameter portion of the through hole is employed as a liquid droplet ejection hole, the manufacturing method comprising: preparing a substrate comprising a first base member composed of Si having an Si anisotropic dry etching rate and a second base member provided directly on a surface of one side of the first base member with an anisotropic dry etching rate and wherein the anisotropic dry etching rate in the second base member is lower than the Si anisotropic dry etching rate in the first base member; forming a film on a surface of the second base member which is to be converted to a second etching mask; forming a second etching mask pattern having an aperture shape of the small diameter portion by applying a photolithography treatment and etching to the film which is to be converted to the second etching mask; carrying out the etching until an etching part is extended through the second base member; forming a film which is to be converted to a first etching mask on a surface of the first base member; forming a first etching mask pattern having an aperture shape of the large diameter portion by applying a photolithography treatment and etching to the film which is to be converted to the first etching mask; and carrying out Si anisotropic dry etching until the first base member is passed through.