Patent ID: 8173030

Claim:
A method for forming a self-aligned hole through a substrate to form a fluid feed passage, the method comprising the steps of forming an insulating layer on a first side of a substrate having two opposing sides; forming a feature on the insulating layer on the substrate; etching an opening through the insulating layer on the substrate, such that the opening is physically aligned with the feature on the insulating layer; coating the feature with a layer of protective material; patterning the layer of protective material to expose the opening through the insulating layer; dry etching from the first side of the substrate to form a blind feed hole in the substrate corresponding to a location of the opening through the insulating layer, the blind feed hole including a bottom; grinding a second side of the substrate to within a distance of 50 microns from the bottom of the blind feed hole; and blanket etching the second side of the substrate to open the bottom of the blind feed hole to form an opening through the entire substrate.