Patent ID: 8765498

Claim:
A method of manufacturing a liquid discharge head substrate, the liquid discharge head substrate including a silicon substrate having a first surface and a second surface opposite the first surface, a liquid supply port being formed in the silicon substrate, the liquid supply port having a first portion that is a recess having an opening in the second surface and having a bottom between the first surface and the second surface and a plurality of second portions that are through-holes passing through from the bottom of the first portion to the first surface, the manufacture method comprising: forming an etching mask layer having an opening in a shape corresponding to the plurality of second portions at the second surface of the silicon substrate; forming non-through holes to be the first portion by etching the silicon substrate through the opening of the etching mask layer from a second surface side of the silicon substrate, wherein the non-though holes are expanded in a direction parallel to the second surface by etching the silicon substrate between the non-through holes so that the none-through holes are connected to each other to form a recess to be the first portion; and forming the plurality of second portions by etching a portion from the bottom of the first portion to the first surface using the etching mask layer as a mask from the second surface side of the silicon substrate to form the liquid supply port passing through the silicon substrate.