Patent ID: 8377828

Claim:
A manufacturing method of a liquid discharge head substrate that includes a silicon substrate having a first surface on which elements for generating energy used to discharge a liquid are provided and a supply port passing through the silicon substrate and being used for supplying the liquid to the elements, the manufacturing method comprising the steps of: providing the silicon substrate having a second surface on which a layer having a lower etching rate, with respect to an etchant, than an etching rate of the silicon substrate, is formed, the second surface being opposite to the first surface; forming a groove penetrating the layer and entering the substrate, the groove being in a frame shape enclosing a portion of the layer inside thereof when the silicon substrate is viewed from the second surface; and forming the supply port in the silicon substrate by wet etching the silicon substrate from the second surface in the frame shape enclosing the portion of the layer inside thereof toward the first surface through the groove using the etchant.