Mandrel for forming a nozzle plate having orifices of precise size and

Abstract

A mandrel for forming a nozzle plate having orifices of precise size and location, and method of making the mandrel. The nozzle plate is formed by overcoating a substrate with a metal film. The film is covered with a photoresist material. Portions of the photoresist are exposed to light passing through a photomask having an annular light-transparent regions, of precise diameters and pitch. The photoresist is subjected to a developer bath which dissolves the photoresist exposed to the light, thereby revealing selected portion of the film. Next, an etchant is brought into contact with the film for etching-away the film so as to an annular opening in the film defining a column of precise diameter at the center of each opening. A new photoresist layer is then applied to the film. Portions of the new photoresist layer is exposed to light passing through a second photomask. The new photoresist material is then subjected to the developer which dissolves the new photoresist material to reveal the film beneath the photoresist and selected areas of the substrate. A second etchant is applied to create an annular recess extending into the substrate. The column resides at the center of the recess. This forms the nozzle plate mandrel. Next, a metal layer that will form the nozzle plate is deposited onto the film and grows into the recess to substantially fill the recess, except for the space occupied by the column. The finished nozzle plate is separated from the film/substrate structure to obtain orifices with precise diameters and pitch.