Thermal ink jet printhead and process therefor

Claim 1

A method for fabricating a printhead for use in an ink jet printing device, comprising the steps of: (a) cleaning first and second silicon substrates (28, 31), each having first and second parallel surfaces, the substrate surfaces being {100} planes; (b) depositing a layer (41) of insulative materials on the surfaces of the substrates; (c) forming an equally spaced, linear array of resistive material elements (34) on the first surface (30) of the first substrate (28) for use as heating elements and forming a pattern of electrodes (33) on the same substrate surface for enabling individual addressing of each heating element with current pulses; (d) photolithographically patterning the insulative layer on the first surface (44) of the second substrate (31) to produce at least one via therein for orientation dependent etching of at least one recess (45) in the second substrate bounded by {111} plane side walls; (e) forming a plurality of equally spaced, parallel grooves (48) in the first surface of the second substrate, one end of the grooves communicating with the recess (45) and the other ends of the grooves being open; (f) applying an adhesive to the insulative layer on the first surface of the second substrate; (g) aligning the first and second substrates - (28, 31) with their first surfaces confronting and contacting each other, so that each groove (48) contains a heating element (34 therein spaced a predetermined distance frorr the groove open end; and (h) curing the adhesive to bond the first ant second substrates together to form the prin thead, wherein the recess (45) serves as ar ink supplying manifold, the grooves (48) serve as capillary filled channels, and the groove open ends serve as the printhead nozzles (27).

Claim 2

A method for fabricating a printhead for use in an ink jet printing device, comprising the steps of: (a) cleaning first and second silicon substrates (28, 31), each having first and second parallel surfaces, the substrate surfaces being {100} planes; (b) depositing a layer (41) of insulative materials on the surfaces of the substrates; (c) forming an equally spaced, linear array of resistive material elements (34) on the first surface (30) of the first substrate (28) for use as heating elements and forming a pattern of electrodes (33) on the same substrate surface for enabling individual addressing of each heating element with current pulses; (d) photolithographically patterning the insulative layer on the first surface (44) of the second substrate (31) to produce at least one via therein for orientation dependent etching of at least one recess (45) in the second substrate bounded by {111} plane side walls; (e) forming a plurality of equally spaced, parallel grooves (48) in the first surface of the second substrate, one end of the grooves communicating with the recess (45) and the other ends of the grooves being open; (f) applying an adhesive to the insulative layer on the first surface of the second substrate; (g) aligning the first and second substrates - (28, 31) with their first surfaces confronting and contacting each other, so that each groove (48) contains a heating element (34 therein spaced a predetermined distance frorr the groove open end; and (h) curing the adhesive to bond the first ant second substrates together to form the prin thead, wherein the recess (45) serves as ar ink supplying manifold, the grooves (48) serve as capillary filled channels, and the groove open ends serve as the printhead nozzles (27).

Claim 7

The method of any one of Claims 1 to 5 wherein the via patterned in step (d) is sized so that the orientation dependent etching etches en tirely through the second substrate, the open bot tom of the recess being for use as a fill hole for the subsequently formed manifold.

Claim 8

The method of any one of Claims 1 to 6 wherein the grooves of step (e) are formed b) concurrent orientation dependent etching with the recess of step (d) by patterning a plurality of nar row, equally spaced, elongated vias in the insula tive layer spaced from and perpendicular to the recess via, the etched grooves being bounded by {111} plane side walls, the longer side walls converging to form grooves with a V-shaped cross-section, and wherein both ends of the grooves are diced open, so that the groove ends closer to the recess are in communication therewith and the other ends are open to serve as nozzles.

Claim 9

The method of any one of Claims 1 to 6, wherein the grooves of step (e) are formed by concurrent orientation dependent etching with the recess of step (d) by patterning a plurality of relatively narrow, equally spaced, elongated vias in the insulative layer spaced from and perpendicular to the recess via, the distance between the ends of the grooves closer to the recess being shorter than the distance between the other ends of the grooves from a one of the second substrate edges, the etched grooves being bounded by {111} plane side walls, and wherein the ends of the grooves adjacent the recess are opened to the recess by first isotropic etching of the second substrate for a period of time sufficient to permit undercutting of the insulative layer between the grooves and the recess, cleaning the second substrate to stop the isotropic etching process, and then, orientation dependent etching of the second substrate a second time in order to open the grooves to the recess since the undercut region is exposed to the orientation dependent etchant, the other ends of the grooves being subsequently diced opened to form the nozzles.

Claim 10

A method for fabricating a plurality of printheads, each printhead being usable in an ink jet printing device for emitting and propelling ink droplets toward a recording medium, the method comprising the steps of: (a) cleaning first and second (100) silicon wafers (28, 31), each having first and second substantially parallel surfaces; (b) depositing a layer of insulative material - (41) on the surfaces of the wafers; (c) forming a plurality of sets of equally spaced, linear arrays of resistive material elements (34) on the insulative layer on the first surface of the first wafer (28) for use as sets of heating elements, and forming a plurality of sets of addressing electrodes (33) on the same wafer surface for enabling individual addressing of each heating element with current pulse; (d) photolithographically patterning the insulative layer on the first surface of the second wafer (31) to produce a plurality of sets of vias (45, 54) of predetermined sizes and at predetermined locations thereon; (e) anisotropically etching the second wafer - (31) to produce sets of recesses (45) in its first surface, each recess being bounded by {111} plane side walls; (f) forming a plurality of sets of equally spaced, parallel grooves (48) through the first surface of the second wafer and its insulative layer each groove having a predetermined depth and first and second ends; the first ends of each set of grooves communicating with an associated one (45) of the set of recesses, the second ends of each set of grooves opening into another of the set of recesses (54); (g) applying an adhesive on the remaining unetched insulative layer of the first surface of the second wafer; (h) aligning the first and second wafers (28, 31) with their first surfaces confronting and contacting each other with the adhesive sandwiched therebetween, the alignment assuring that each groove (48) contains one of the heating elements (34) spaced a predetermined distance from the second, open, end thereof; (i) curing the adhesive to bond the first and second wafers together, so that each recess - (45) in the set of recesses communicating with a set of grooves serves as an ink supplying - manifold, while each set of grooves (48) serves as capillary filling channels, with the second, open, end of. the grooves serving as nozzles (27); and . (i) dicing the bonded wafers into a plurality of individual printheads, each printhead having a manifold (45), a set of channels (48) communicating with the manifold at one end thereof and having nozzles (27) at the other end with heating elements (34) in each a predetermined distance from the nozzles, and addressing electrodes (33) for selectively addressing the heating elements.

Claim 11

A method for fabricating a plurality of printheads, each printhead being usable in an ink jet printing device for emitting and propelling ink droplets toward a recording medium, the method comprising the steps of: (a) cleaning first and second (100) silicon wafers (28, 31), each having first and second substantially parallel surfaces; (b) depositing a layer of insulative material - (41) on the surfaces of the wafers; (c) forming a plurality of sets of equally spaced, linear arrays of resistive material elements (34) on the insulative layer on the first surface of the first wafer (28) for use as sets of heating elements, and forming a plurality of sets of addressing electrodes (33) on the same wafer surface for enabling individual addressing of each heating element with current pulse; (d) photolithographically patterning the insulative layer on the first surface of the second wafer (31) to produce a plurality of sets of vias (45, 54) of predetermined sizes and at predetermined locations thereon; (e) anisotropically etching the second wafer - (31) to produce sets of recesses (45) in its first surface, each recess being bounded by {111} plane side walls; (f) forming a plurality of sets of equally spaced, parallel grooves (48) through the first surface of the second wafer and its insulative layer each groove having a predetermined depth and first and second ends; the first ends of each set of grooves communicating with an associated one (45) of the set of recesses, the second ends of each set of grooves opening into another of the set of recesses (54); (g) applying an adhesive on the remaining unetched insulative layer of the first surface of the second wafer; (h) aligning the first and second wafers (28, 31) with their first surfaces confronting and contacting each other with the adhesive sandwiched therebetween, the alignment assuring that each groove (48) contains one of the heating elements (34) spaced a predetermined distance from the second, open, end thereof; (i) curing the adhesive to bond the first and second wafers together, so that each recess - (45) in the set of recesses communicating with a set of grooves serves as an ink supplying - manifold, while each set of grooves (48) serves as capillary filling channels, with the second, open, end of. the grooves serving as nozzles (27); and . (i) dicing the bonded wafers into a plurality of individual printheads, each printhead having a manifold (45), a set of channels (48) communicating with the manifold at one end thereof and having nozzles (27) at the other end with heating elements (34) in each a predetermined distance from the nozzles, and addressing electrodes (33) for selectively addressing the heating elements.