Silicon substrate processing method and liquid ejection head manufacturing method

Abstract

Provided is a silicon substrate processing method including: providing a silicon substrate with a sacrificial layer formed in the form of an island on the front surface thereof, the front surface being a surface on a side where the flow path of an ejection port for ejecting liquid is to be formed, the sacrificial layer having a higher etching rate than the silicon substrate; forming a mask layer on the back surface, the back surface being a surface opposite from the front surface, the mask layer being a layer that does not include an opening at a portion of the back surface opposite from the sacrificial layer; forming a non-penetrating hole from an opening on the back surface of the silicon substrate; and forming a beam on the back surface side by performing anisotropic etching on the silicon substrate in which the non-penetrating hole is formed.