Method for manufacturing liquid discharge head, substrate for liquid discharge head and method for working substrate

摘要

An ink supply port is opened in an Si substrate on which an ink discharge energy generating element is formed, by anisotropic etching, from a back surface opposite to a surface on which the ink discharge energy generating element is formed. When the anisotropic etching is effected, OSF (oxidation induced laminate defect) remaines on the back surface of the Si substrate with OSF density equal to or greater than 2x10⁴ parts/cm² and a length of OSF equal to or greater than 2 mum.