Method of fabricating through hole and nozzle plate of ink jet printhead device

A method of fabricating a through hole of an ink jet printhead device is disclosed, wherein the printhead device may be a printhead chip or a nozzle plate. In this disclosure, the method of fabricating a through hole of an ink jet printhead chip is to coat a surface of the ink jet printhead chip with a photosensitive material layer. An exposure process is performed to the photosensitive material layer for defining a pattern. A development process is then performed to the exposed photosensitive material layer for forming a photosensitive material pattern. Thereafter, the surface of the ink jet printhead chip coated with the photosensitive material pattern is etched to form a through hole by means of inductively coupled plasma and utilizing the photosensitive material pattern as a mask, wherein the angle between the surface opposite to the etched surface of the ink jet printhead chip and an inner surface of the through hole is an obtuse angle. The method of fabricating a through hole of a nozzle plate is the same as the abovementioned method.