Thermal ink jet printhead fabricating process

Claim 1

A method for fabricating a roofshooter type thermal ink jet printhead for use in a drop-on-demand, ink jet printing device, comprising the steps of: (a) cleaning a silicon substrate having first and second parallel surfaces, the substrate surfaces being {100} planes; (b) depositing a layer of substantially transparent insulating material on the substrate surfaces; (c) patterning the insulative layer on one of the surfaces of the substrate to produce a predetermined number of alignment means thereon; (d) producing the predetermined number of alignment means on said one of the substrate surfaces; (e) forming a plurality of equally spaced, linear arrays or resistive material on the insulative layer of the first surface of the substrate for subsequent use as arrays of heating elements; (f) depositing a pattern of electrodes on the insulative layer of the substrate first surface to enable individual addressing of each heating element with electrical pulses; (g) applying a passivation layer over the insulative layer of the first surface of the substrate, including the electrode and the heating elements thereon; (h) patterning the insulative layer on the second surface of the substrate using the alignment means to produce a plurality of elongated vias therein; (i) placing the substrate in an anisotropic etchant for orientation dependent etching (ODE) thereof to produce elongated openings therethrough bounded by {111} planes which open against and are covered by the passivation layer and insulative layer on the substrate first surface, the elongated openings each being longitudinally aligned adjacent a respective one of the arrays of heating elements in a precise predetermined location; (j) patterning and etching the passivation layer to expose ends of the electrodes that are to serve subsequently as electrical contact pads, to open windows over the heating elements, and to produce an elongated openings through the substrate by removing the insulative material and passivation layer over the etched elongated openings, so that the elongated openings may serve subsequently as both ink fill inlets and as ink reservoirs; (k) aligning and attaching a structural member to the first surface of the substrate, the structural member containing a plurality of recessed cavities, each having a plurality of parallel walls therein and each having a plurality of nozzles communicating with a respective cavity, the nozzles being located such that one nozzle is located between each pair of walls and above a respective heating element, each cavity being in communication with a respective elongated opening in the substrate, so that each combination of cavity and elongated opening form a complete ink reservoir, with the elongated opening portion of the reservoir capable of containing more ink than the the cavity portion of the reservoir; and (l) dicing the substrate and attached structural member into a plurality of individual printheads.

Claim 2

A method for fabricating a roofshooter type thermal ink jet printhead for use in a drop-on-demand, ink jet printing device, comprising the steps of: (a) cleaning a silicon substrate having first and second parallel surfaces, the substrate surfaces being {100} planes; (b) depositing a layer of substantially transparent insulating material on the substrate surfaces; (c) patterning the insulative layer on one of the surfaces of the substrate to produce a predetermined number of alignment means thereon; (d) producing the predetermined number of alignment means on said one of the substrate surfaces; (e) forming a plurality of equally spaced, linear arrays or resistive material on the insulative layer of the first surface of the substrate for subsequent use as arrays of heating elements; (f) depositing a pattern of electrodes on the insulative layer of the substrate first surface to enable individual addressing of each heating element with electrical pulses; (g) applying a passivation layer over the insulative layer of the first surface of the substrate, including the electrode and the heating elements thereon; (h) patterning the insulative layer on the second surface of the substrate using the alignment means to produce a plurality of elongated vias therein; (i) placing the substrate in an anisotropic etchant for orientation dependent etching (ODE) thereof to produce elongated openings therethrough bounded by {111} planes which open against and are covered by the passivation layer and insulative layer on the substrate first surface, the elongated openings each being longitudinally aligned adjacent a respective one of the arrays of heating elements in a precise predetermined location; (j) patterning and etching the passivation layer to expose ends of the electrodes that are to serve subsequently as electrical contact pads, to open windows over the heating elements, and to produce an elongated openings through the substrate by removing the insulative material and passivation layer over the etched elongated openings, so that the elongated openings may serve subsequently as both ink fill inlets and as ink reservoirs; (k) aligning and attaching a structural member to the first surface of the substrate, the structural member containing a plurality of recessed cavities, each having a plurality of parallel walls therein and each having a plurality of nozzles communicating with a respective cavity, the nozzles being located such that one nozzle is located between each pair of walls and above a respective heating element, each cavity being in communication with a respective elongated opening in the substrate, so that each combination of cavity and elongated opening form a complete ink reservoir, with the elongated opening portion of the reservoir capable of containing more ink than the the cavity portion of the reservoir; and (l) dicing the substrate and attached structural member into a plurality of individual printheads.