Patent ID: 8377321

Claim:
A method of forming a nozzle and an ink chamber of an ink jet device, comprising the steps of: forming a nozzle passage by subjecting a substrate to a directional first etch process from one side of the substrate; applying a second etch process from the same side of the substrate for widening an internal part of the nozzle passage, to form a cavity forming at least a portion of the ink chamber adjacent to the nozzle; and controlling the shape of the cavity by providing, on the opposite side of the substrate, an underlying layer buried under an etch stop layer and by allowing the second etch process to proceed into the underlying layer, wherein the second etch process takes place in the underlying layer at a higher etching rate than in the etch stop layer and the substrate, wherein the following steps precede the first etch process: forming an annular trench in the substrate on the side of the substrate where the nozzle is to be formed; and passivating the walls of the trench so as to become resistant against the second etch process, and wherein the material surrounded by the trench is removed in the first etch process.