Patent ID: 6858152

Claim:
A method for manufacturing a liquid discharge head, comprising: a step for preparing an Si substrate having a first surface as an element forming surface and a second surface as a back surface opposite to the first surface; a step for effecting heat treatment by heating of said Si substrate; a step for forming an SiO 2 film on the second surface of said Si substrate; a step for forming an etching start opening portion in said SiO 2 film to expose said Si substrate; a step for forming a liquid discharge energy generating element for generating energy for discharging liquid on the first surface of said Si substrate; and a step for forming a liquid supply port passing through said Si substrate and communicated with the first surface from said etching start opening portion by anisotropic etching of Si using said SiO 2 film as a mask, after said heat treatment step, wherein, before the anisotropic etching is effected, the density of oxidation induced laminate defects existing in an interface between said Si substrate and said SiO 2 film is made to be equal to or greater than 2×10 4 parts/cm 2 .