Patent ID: 7229157

Claim:
In an inkjet printhead comprised of a silicon substrate of a given thickness and having a front surface and a rear flat surface opposite and parallel to the front surface, both surfaces being protected by a passivating layer of dielectric material, the silicon substrate having a plurality of layers deposited on the front surface with a plurality of ink ejection cells arranged in the layers to be fed with ink through a feeding duct traversing the silicon substrate, a method for constructing the feeding duct, comprising: a first step of eroding the silicon substrate first from the rear surface to a predetermined depth to form a cavity having a rear wall separated from the front surface by a diaphragm; a second step of next eroding the silicon substrate from the front surface for etching a channel to a predetermined depth and defining a contour of an outlet area communicating with the ink ejection cells; and a third step of subsequently eroding the silicon substrate from the rear surface to remove the diaphragm to form the feeding duct between the rear and front surfaces.