Method for manufacturing a thermal ink-jet print head

Claim 1

A method for fabricating ink fill slots 18 for fluidically communicating with ink feed channels 14 in thermal ink-jet printheads 13 , comprising: (a) providing a silicon substrate 12 having a <100> or <110> crystallographic orientation and two opposed, substantially parallel major surfaces 12a , 12b , defining a primary surface 12a and a secondary surface 12b; (b) forming an insulating dielectric layer 26 on both said surfaces 12a , 12b; (c) patterning said insulating dielectric layer 26 on said secondary surface 12b to expose underlying portions of said silicon substrate 12 ; (d) etching part way through said silicon substrate 12 with an anisotropic etchant at said exposed portions to thereby form a portion 18' of said ink fill slot 18 ; and either (e1) forming and defining thin film resistor elements 16 and conductive traces on said insulating dielectric layer 26 on said primary surface 12a ; (f1) etching from said primary surface 12a to connect with said portion of said ink fill slot 18' to thereby completely form said ink fill slot 18 and to extend the portion of said ink fill slot 18 terminating at said primary surface toward said ink feed channels 14 to cause a widening thereof 18a ; and (g1) forming a barrier layer 17 on the major surface of said dielectric material 26 and defining openings therein to expose said resistor elements 16 to define a drop ejection chamber 15 and to provide said ink feed channels 14 from each said resistor element 16 to a terminus region A , said terminus region A fluidically communicating with said ink fill slot 18 for introducing ink from a reservoir to said drop ejection chamber 15 , whereby the shelf length defined by the distance from the entrance to said ink feed channel 14 and said ink fill slot 18 is decreased; or (e2) forming a barrier layer 17 on the major surface of said dielectric material 26 and defining openings therein to expose said resistor elements 16 to define a drop ejection chamber 15 and to provide an ink feed channel 14 from each said resistor element 16 to a terminus region A , said terminus region A fluidically communicating with said ink fill slot 18 for introducing ink from a reservoir to said drop ejection chamber 15 , said ink fill slot 18 precisely defined relative to said terminus region A ; and (f2) micromachining from said secondary surface 12b to connect with said portion 18' of said ink fill slot 18 to thereby completely form said ink fill slot 18 , whereby the shelf length defined by the distance from the entrance to said ink feed channel 14 and said ink fill slot 18 is decreased.