# Patent

## Title
Fluid-ejecting integrated circuit utilizing electromagnetic displacement

## Abstract

A fluid ejecting integrated circuit (IC) includes a nozzle chamber defined by chamber side walls extending from a wafer substrate, and a roof wall provided on the chamber side walls; a fluid ejecting member provided within the nozzle chamber between the roof wall of the nozzle chamber and the wafer substrate; a support formation provided within the nozzle chamber and spaced inwardly away from the chamber side walls, the support formation extending from the wafer substrate to support the fluid ejecting member thereon; a first planar electrode layered to the fluid ejecting member; a second planar electrode layered on the wafer substrate; and a projection provided on the first planar electrode on a side facing the second planar electrode, the projection for contacting the second planar electrode to prevent contact between the first planar electrode and the second planar electrode. The first and second planar electrode establish a potential therebetween to deform the first planar electrode towards the second planar electrode.

## Background
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of U.S. application Ser. No. 11/583,826 filed on Oct. 20, 2006, which is a continuation of U.S. application Ser. No. 10/957,718 filed on Oct. 5, 2004, now issued as U.S. Pat. No. 7,140,723, which is a continuation of U.S. application Ser. No. 10/184,883 filed on Jul. 1, 2002, now issued as U.S. Pat. No. 6,820,968, which is a continuation of U.S. application Ser. No. 09/113,070 filed Jul. 10, 1998, now issued as U.S. Pat. No. 6,476,863, the entire contents of which are herein incorporated by reference.
The following Australian provisional patent applications are hereby incorporated by cross-reference. For the purposes of location and identification, US patent applications identified by their US patent application serial numbers (USSN) are listed alongside the Australian applications from which the U.S. patent applications claim the right of priority.
















US Patent Application




Cross-Referenced
(Claiming Right



Australian
of Priority from



Provisional
Australian Provisional



Patent No.
Application)
Docket No.









PO7991
6,750,901
ART01US



PO8505
6,476,863
ART02US



PO7988
6,788,336
ART03US



PO9395
6,322,181
ART04US



PO8017
6,597,817
ART06US



PO8014
6,227,648
ART07US



PO8025
6,727,948
ART08US



PO8032
6,690,419
ART09US



PO7999
6,727,951
ART10US



PO8030
6,196,541
ART13US



PO7997
6,195,150
ART15US



PO7979
6,362,868
ART16US



PO7978
6,831,681
ART18US



PO7982
6,431,669
ART19US



PO7989
6,362,869
ART20US



PO8019
6,472,052
ART21US



PO7980
6,356,715
ART22US



PO8018
6,894,694
ART24US



PO7938
6,636,216
ART25US



PO8016
6,366,693
ART26US



PO8024
6,329,990
ART27US



PO7939
6,459,495
ART29US



PO8501
6,137,500
ART30US



PO8500
6,690,416
ART31US



PO7987
7,050,143
ART32US



PO8022
6,398,328
ART33US



PO8497
7,110,024
ART34US



PO8020
6,431,704
ART38US



PO8504
6,879,341
ART42US



PO8000
6,415,054
ART43US



PO7934
6,665,454
ART45US



PO7990
6,542,645
ART46US



PO8499
6,486,886
ART47US



PO8502
6,381,361
ART48US



PO7981
6,317,192
ART50US



PO7986
6,850,274
ART51US



PO8026
6,646,757
ART53US



PO8028
6,624,848
ART56US



PO9394
6,357,135
ART57US



PO9397
6,271,931
ART59US



PO9398
6,353,772
ART60US



PO9399
6,106,147
ART61US



PO9400
6,665,008
ART62US



PO9401
6,304,291
ART63US



PO9403
6,305,770
ART65US



PO9405
6,289,262
ART66US



PP0959
6,315,200
ART68US



PP1397
6,217,165
ART69US



PP2370
6,786,420
DOT01US



PO8003
6,350,023
Fluid01US



PO8005
6,318,849
Fluid02US



PO8066
6,227,652
IJ01US



PO8072
6,213,588
IJ02US



PO8040
6,213,589
IJ03US



PO8071
6,231,163
IJ04US



PO8047
6,247,795
IJ05US



PO8035
6,394,581
IJ06US



PO8044
6,244,691
IJ07US



PO8063
6,257,704
IJ08US



PO8057
6,416,168
IJ09US



PO8056
6,220,694
IJ10US



PO8069
6,257,705
IJ11US



PO8049
6,247,794
IJ12US



PO8036
6,234,610
IJ13US



PO8048
6,247,793
IJ14US



PO8070
6,264,306
IJ15US



PO8067
6,241,342
IJ16US



PO8001
6,247,792
IJ17US



PO8038
6,264,307
IJ18US



PO8033
6,254,220
IJ19US



PO8002
6,234,611
IJ20US



PO8068
6,302,528
IJ21US



PO8062
6,283,582
IJ22US



PO8034
6,239,821
IJ23US



PO8039
6,338,547
IJ24US



PO8041
6,247,796
IJ25US



PO8004
6,557,977
IJ26US



PO8037
6,390,603
IJ27US



PO8043
6,362,843
IJ28US



PO8042
6,293,653
IJ29US



PO8064
6,312,107
IJ30US



PO9389
6,227,653
IJ31US



PO9391
6,234,609
IJ32US



PP0888
6,238,040
IJ33US



PP0891
6,188,415
IJ34US



PP0890
6,227,654
IJ35US



PP0873
6,209,989
IJ36US



PP0993
6,247,791
IJ37US



PP0890
6,336,710
IJ38US



PP1398
6,217,153
IJ39US



PP2592
6,416,167
IJ40US



PP2593
6,243,113
IJ41US



PP3991
6,283,581
IJ42US



PP3987
6,247,790
IJ43US



PP3985
6,260,953
IJ44US



PP3983
6,267,469
IJ45US



PO7935
6,224,780
IJM01US



PO7936
6,235,212
IJM02US



PO7937
6,280,643
IJM03US



PO8061
6,284,147
IJM04US



PO8054
6,214,244
IJM05US



PO8065
6,071,750
IJM06US



PO8055
6,267,905
IJM07US



PO8053
6,251,298
IJM08US



PO8078
6,258,285
IJM09US



PO7933
6,225,138
IJM10US



PO7950
6,241,904
IJM11US



PO7949
6,299,786
IJM12US



PO8060
6,866,789
IJM13US



PO8059
6,231,773
IJM14US



PO8073
6,190,931
IJM15US



PO8076
6,248,249
IJM16US



PO8075
6,290,862
IJM17US



PO8079
6,241,906
IJM18US



PO8050
6,565,762
IJM19US



PO8052
6,241,905
IJM20US



PO7948
6,451,216
IJM21US



PO7951
6,231,772
IJM22US



PO8074
6,274,056
IJM23US



PO7941
6,290,861
IJM24US



PO8077
6,248,248
IJM25US



PO8058
6,306,671
IJM26US



PO8051
6,331,258
IJM27US



PO8045
6,110,754
IJM28US



PO7952
6,294,101
IJM29US



PO8046
6,416,679
IJM30US



PO9390
6,264,849
IJM31US



PO9392
6,254,793
IJM32US



PP0889
6,235,211
IJM35US



PP0887
6,491,833
IJM36US



PP0882
6,264,850
IJM37US



PP0874
6,258,284
IJM38US



PP1396
6,312,615
IJM39US



PP3989
6,228,668
IJM40US



PP2591
6,180,427
IJM41US



PP3990
6,171,875
IJM42US



PP3986
6,267,904
IJM43US



PP3984
6,245,247
IJM44US



PP3982
6,315,914
IJM45US



PP0895
6,231,148
IR01US



PP0869
6,293,658
IR04US



PP0887
6,614,560
IR05US



PP0885
6,238,033
IR06US



PP0884
6,312,070
IR10US



PP0886
6,238,111
IR12US



PP0877
6,378,970
IR16US



PP0878
6,196,739
IR17US



PP0883
6,270,182
IR19US



PP0880
6,152,619
IR20US



PO8006
6,087,638
MEMS02US



PO8007
6,340,222
MEMS03US



PO8010
6,041,600
MEMS05US



PO8011
6,299,300
MEMS06US



PO7947
6,067,797
MEMS07US



PO7944
6,286,935
MEMS09US



PO7946
6,044,646
MEMS10US



PP0894
6,382,769
MEMS13US












FIELD OF THE INVENTION
The present invention relates to fluid dispensing. In particular, this invention discloses a micro-electromechanical fluid-dispensing device.
BACKGROUND OF THE INVENTION
This invention is a development of a printing technology that has been developed by the Applicant. This development can be traced by considering the referenced patents/patent applications set out above.
Many different types of printing have been invented, a large number of which are presently in use. The known forms of printing have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
Many different techniques of ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, “Non-Impact Printing: Introduction and Historical Perspective”, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
Ink Jet printers themselves come in many different types. The utilisation of a continuous stream of ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electro-static ink jet printing.
U.S. Pat. No. 3,596,275 by Sweet also discloses a process of continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al)
Piezoelectric ink jet printers are also one form of commonly utilized ink jet printing device. Piezoelectric systems are disclosed by Kyser et al. in U.S. Pat. No. 3,946,398 (1970) which utilises a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezo-electric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a Piezoelectric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a sheer mode type of piezoelectric transducer element.
Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclosed ink jet printing techniques rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Manufacturers such as Canon and Hewlett Packard manufacture printing devices utilising the electro-thermal actuator.
As can be seen in the above referenced matters, Applicant has developed an ink jet printing technology that uses micro-electromechanical components to achieve the ejection of ink. The use of micro-electromechanical components allows printhead chips to have a large number of densely packed nozzle arrangements without the problems associated with heat build-up.
Applicant envisages that this technology can be used to dispense fluid. This invention is therefore intended to be a simple development of the technology that has already been the subject of many patent applications filed by the Applicant.
SUMMARY OF THE INVENTION
According to an aspect of the present disclosure, a fluid ejecting integrated circuit (IC) includes a nozzle chamber defined by chamber side walls extending from a wafer substrate, and a roof wall provided on the chamber side walls; a fluid ejecting member provided within the nozzle chamber between the roof wall of the nozzle chamber and the wafer substrate; a support formation provided within the nozzle chamber and spaced inwardly away from the chamber side walls, the support formation extending from the wafer substrate to support the fluid ejecting member thereon; a first planar electrode layered to the fluid ejecting member; a second planar electrode layered on the wafer substrate; and a projection provided on the first planar electrode on a side facing the second planar electrode, the projection for contacting the second planar electrode to prevent contact between the first planar electrode and the second planar electrode. The first and second planar electrode establish a potential therebetween to deform the first planar electrode towards the second planar electrode.



BRIEF DESCRIPTION OF THE DRAWINGS
Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a sectioned side view of one embodiment of a fluid-dispensing chip of the invention, in an operative condition.
FIG. 2 is a sectioned side view of the fluid-dispensing chip of FIG. 1 in a quiescent condition.
FIG. 3 is a perspective cross-sectional view of another embodiment of the fluid-dispensing chip of the invention.
FIG. 4 is a close-up perspective cross-sectional view (portion A of FIG. 3), of the fluid-dispensing chip of FIG. 3.
FIG. 5 is an exploded perspective view illustrating the construction of the fluid-dispensing chip of FIG. 3.



DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS
In FIGS. 1 and 2, reference numeral 10 generally indicates a sectioned side view of one embodiment of a fluid-dispensing chip of the invention.
The fluid-dispensing chip may include a silicon wafer substrate 12. A drive circuitry layer 14 is positioned on the wafer substrate 12. The drive circuitry layer 14 is in the form of a CMOS two-level metal layer that includes the drive and control circuitry for the fluid-dispensing chip 10.
A passivation layer 16 of silicon nitride is positioned on the drive circuitry layer 14 to protect the drive circuitry layer 14. A first planar electrode 18 is embedded in the layer 16. The first planar electrode 18 is of aluminum and is connected to the drive circuitry layer 14.
The fluid-dispensing chip 10 includes a nozzle chamber wall 19 and a roof wall 20 that define a nozzle chamber 22. The roof wall 20 defines a fluid ejection port 44. A fluid-ejecting member 28 is positioned in the nozzle chamber 22. The fluid-ejecting member 28 is planar and is aligned with and parallel to the first planar electrode 18.
The fluid-ejecting member 28 is positioned on a support formation 34 that extends from the passivation layer 16. The support formation 34 is dimensioned so that the fluid-ejecting member 28 is spaced a suitable distance from the first electrode 18. The support formation 34 is configured so that an air gap 40 is encapsulated between the fluid-ejecting member 28 and the first electrode 18.
The fluid-ejecting member 28 includes a second planar electrode 24 that is positioned in the nozzle chamber 22. The second planar electrode 24 is also of aluminum and is also connected to the drive circuitry layer 14. The drive circuitry layer 14 is connected to each of the electrodes 18, 24 so that a potential can be set up between the electrodes 18, 24 so that they are attracted to one another. A layer 26 of silicon nitride is positioned on the electrode 24 to impart a resilient flexibility to the fluid-ejecting member 28. Thus, when a potential is set up between the electrodes 18, 24, the fluid-ejecting member 28 is deflected towards the first electrode 18, as shown in FIG. 1. When the potential is removed, the first electrode 18 returns to a quiescent position as shown in FIG. 2.
A layer 32 of polytetrafluoroethylene (PTFE) is positioned on the first electrode 18. A layer 36 of PTFE is positioned on the second electrode 24, intermediate the electrodes 18, 24. This ensures that the electrodes 18, 24 do not stick to one another when the fluid-ejecting member 28 is deflected towards the first electrode 18. In order further to prevent stiction between the electrodes 18, 24, a projection 38 is positioned on the fluid-ejecting member 28. The projection 38 bears against the layer 32 to ensure that there is no contact between the layers 32, 36.
The nozzle chamber wall 19 defines fluid inlet openings 30 that are in fluid communication with a fluid supply so that the nozzle chamber 22 can be supplied with fluid. Fluid flows into a space 41 defined by the roof wall 20, the nozzle chamber wall 19, the fluid-ejecting member 28 and the support formation 34. It will be appreciated that this occurs when the fluid-ejecting member 28 is drawn towards the first electrode 18. When the potential is reversed, the fluid-ejecting member 28 is urged away from the first electrode 18 so that a drop 42 of fluid is ejected from the fluid ejection port 44. The fluid-ejecting member 28 could have sufficient resilience so that a reversal of potential is not necessary. In this case, release of elastic energy as the fluid-ejecting member 28 returns to its quiescent condition ensures the ejection of the fluid drop 42.
The roof wall 20 defines a rim 46 about the fluid ejection port 44.
In FIGS. 3 to 5, reference numeral 50 generally indicates another embodiment of a fluid-dispensing chip of the invention. With reference to FIGS. 1 and 2, like reference numerals refer to like parts, unless otherwise specified.
The fluid-ejecting member 28 has a peripheral portion 52 that is positioned between the nozzle chamber wall 19 and the layer 26 of silicon nitride. A corrugated annular portion 54 is positioned adjacent to the peripheral portion 52. A fluid-ejecting portion 56 defines a remainder of the fluid-ejecting member 28.
The electrodes 18, 24 and their respective PTFE layers 32, 36 are dimensioned to define the air gap 40.
The corrugated portion 54 is configured to expand when the second electrode 24 is displaced towards the first electrode 18. The silicon nitride layer 26 imparts a resilient flexibility to the corrugated portion 54. Thus, the second electrode 24 returns to a quiescent condition when the electrical potential is removed.
The nozzle chamber wall 19 is shaped to define four radially spaced fluid inlet supply channels 58 that are in fluid communication with the space 41. These allow fluid to flow into the space 41 when the second electrode 24 is drawn towards the first electrode 18.
The nozzle chamber wall 19 defines air spaces 60 that are in fluid communication with the air gap 40. These allow the passage of air when the second electrode 24 moves towards and away from the first electrode 18.
The roof wall 20 has a plurality of etchant openings 62 defined therein to facilitate the etching of sacrificial material used in the fabrication of the chip 50. The etchant openings 62 are small enough to inhibit the passage of fluid as a result of surface tension effects.
It is important to note that the fluid-dispensing chip 10, 50 is essentially a micro-electromechanical systems (MEMS) device. A method for fabricating the device can readily be deduced from the description in referenced application no: U.S. Ser. No. 09/112,787 and in many of the other referenced applications.
Applicant envisages that the fluid-dispensing chip 10, 50 will be particularly suited for lab-on-a-chip applications. It can also be applied to DNA/RNA arrays, protein chips and sensing and dosing. The fluid-dispensing chip 10, 50 could also be used for drug delivery systems.
Numerous variations and/or modifications may be made to the present invention as shown in the preferred embodiment without departing from the spirit or scope of the invention as broadly described. The preferred embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.

## Claims

1. A fluid ejecting integrated circuit (IC), the IC comprising:
a nozzle chamber defined by chamber side walls extending from a wafer substrate, and a roof wall provided on the chamber side walls;
a fluid ejecting member provided within the nozzle chamber between the roof wall of the nozzle chamber and the wafer substrate;
a support formation provided within the nozzle chamber and spaced inwardly away from the chamber side walls, the support formation extending from the wafer substrate to support the fluid ejecting member thereon;
a first planar electrode layered to the fluid ejecting member;
a second planar electrode layered on the wafer substrate; and
a projection provided on the first planar electrode on a side facing the second planar electrode, the projection for contacting the second planar electrode to prevent contact between the first planar electrode and the second planar electrode, wherein
the first and second planar electrode establish a potential therebetween to deform the first planar electrode towards the second planar electrode,
the chamber side walls define air spaces that are in fluid communication with an air gap between the planar electrodes, and
one of the planar electrodes includes corrugated portion configured to expand when said one of the electrodes is displaced in the air gap towards the other electrode and is provided with a layer of silicon nitride for imparting a resilient flexibility to the corrugated portion.

2. A fluid ejecting IC as claimed in claim 1, wherein the second planar electrode is coated with a plastic layer on a side facing the first planar electrode.

3. A fluid ejecting IC as claimed in claim 1, wherein the roof wall defines a raised rim defining a fluid ejection port.

4. A fluid ejecting IC as claimed in claim 1, further comprising a drive circuitry layer provided on the wafer substrate.

5. A fluid ejecting IC as claimed in claim 1, further comprising a fluid inlet opening defined through the chamber side wall, the fluid inlet opening providing fluid communication into the nozzle chamber.