Patent ID: 6517735
Filing Date: 2003-02-11
Classification: B41J,Y10T

Abstract:
A method for forming a printing device comprising:providing a printhead substrate; forming a polysilicon layer over a first surface of said substrate, said polysilicon layer having peripheral portions for defining edges of a trench to be subsequently formed in said substrate, said peripheral portions being aligned with a boundary of ink feed holes, to be later formed; forming a plurality of thin film layers on said first surface of said substrate, at least one of said layers forming a plurality of ink ejection elements; forming ink feed openings through at least some of said thin film layers; forming an orifice layer over said thin film layers, said orifice layer defining a plurality of ink ejection chambers, each chamber having within it an ink ejection element, said orifice layer further defining a nozzle for each ink ejection chamber; masking a second surface of said substrate to perform a trench etch; etching said second surface of said substrate using a wet etchant to form a trench, said etching also etching said polysilicon layer, said trench having at least some edges aligned with said peripheral portions of said polysilicon layer; and wet etching portions of said thin film layers exposed through said ink feed openings and by said trench to self-align edges of said trench substantially to said ink feed holes formed completely through said thin film layers.