Patent ID: 8206998

Claim:
A method for manufacturing a substrate for a liquid discharge head provided with a silicon substrate having an energy-generating element which generates energy utilized for discharging a liquid on a first surface side, and a supply port for supplying the liquid to the energy-generating element, comprising the following in this order: providing the silicon substrate having an insulating layer consisting of an insulating material on the first surface and an etching mask layer having a plurality of apertures on a second surface which is a rear surface of the first surface, wherein the insulating layer is provided in a region ranging from a position opposing the inside of the aperture to a position opposing a portion between the adjacent apertures of the mask layer; and forming holes to be the supply ports corresponding to the plurality of the adjacent apertures by etching a silicon part of the silicon substrate from the plurality of the apertures with a reactive ion etching technique so that an etched region reaches a portion opposing the inside of the aperture of the insulating layer, while using the etching mask layer as a mask, wherein the silicon wall provided between the adjacent holes is etched with the reactive ion etching technique so that the portion in the first surface side thereof can be thinner than the portion in the second surface side thereof.