Nozzle plate, fluid ejection head, fluid ejection device and nozzle plate improvement method

Abstract

A nozzle plate configured for a fluid ejection head, a fluid ejection head including the nozzle plate, a fluid ejection device including the fluid ejection head, and a method for improving a nozzle plate of a fluid ejection device to reduce fluid overflow on the nozzle plate are provided. The nozzle plate includes a plurality of nozzle holes therein. The nozzle plate is attached to a flow feature layer on a semiconductor substrate. The nozzle plate includes a first drain region surrounding each of the plurality of nozzle holes, whereby the first drain region is configured to reduce overflow of the nozzle plate.

Description

Technical Field

[0001] The present disclosure relates to an improved photoimageable nozzle member for a fluid ejection device, and a method and structure for reducing fluid overflow relative to adjacent nozzle holes during fluid ejection, and more particularly to an improved nozzle plate, a fluid ejection head, a fluid ejection device, and a method for improving a nozzle plate. Background Art

[0002] Flooding, weeping, or drooling is a common phenomenon in fluid ejection devices, especially those associated with fluid dispensing, in which the meniscus of the ejected fluid detaches from the nozzle orifice boundary and spreads across the nozzle plate surface. For the purposes of this disclosure, "flooding" is defined as the undesirable accumulation of fluid on the surface of the ejection head. Flooding can lead to cross-contamination between ejected fluids, degrade the performance of the device, or even render the device inoperable without intervention.

[0003] Typically, overflow occurs due to suboptimal device design for a given set of fluid properties or due to incorrect dispensing parameters, resulting in unstable dispensing. A desirable characteristic of a jet head for hydrophilic fluids (e.g., ink) is to have a hydrophobic jet face that both prevents overflow and minimizes the spread of the fluid across the nozzle plate when overflow does occur. If the fluid ejection device is operated so that it dispenses only in brief bursts, overflows can sometimes self-correct once stable conditions are restored and the fluid is able to return to the nozzles from which it was ejected. However, when overflow occurs in a chain across multiple nozzles, the device cannot self-correct even after returning to a stable condition, and the overflow must be removed mechanically, typically by wiping the nozzle plate.

[0004] The potential for flooding is typically considered during the design of the jet head for a standard horizontal orientation of the jet head with the nozzles pointing in a downward direction. Flooding chains are more likely to occur when the jet head is reoriented so that the nozzle plate is oriented horizontally and the nozzles are pointing in an upward direction, when the nozzle plate is oriented non-horizontally, and when the nozzle plate is vertical and the nozzles are pointing perpendicular to gravity. In the vertical orientation, flooding is further exacerbated by gravity pulling the unstable meniscus toward the nozzles adjacently below the nozzle ejecting the fluid.

[0005] Therefore, there is a need for a spray head having features to inhibit overflow or redirect overflow away from adjacent nozzles, particularly when the spray head is operated in a non-standard orientation. Summary of the invention

[0006] In view of the foregoing, embodiments of the present disclosure provide a nozzle plate configured for a fluid ejection head, a fluid ejection head including the nozzle plate, and a method for improving the nozzle plate to reduce fluid overflow on the nozzle plate. The nozzle plate includes a plurality of nozzle holes, the nozzle plate is attached to a flow feature layer on a semiconductor substrate, and the nozzle plate includes a first hydrophobic region, the first hydrophobic region surrounds each of the plurality of nozzle holes, whereby the first hydrophobic region is configured to reduce overflow of the nozzle plate.

[0007] In some embodiments, a second hydrophobic layer is disposed on an exposed surface of the nozzle plate, wherein the second hydrophobic layer has a raised hydrophobic region relative to the first hydrophobic region.

[0008] In some embodiments, the nozzle plate includes: a hydrophilic region adjacent to the first hydrophobic region.

[0009] In some embodiments, the nozzle plate has a raised second hydrophobic region located above the hydrophilic region, wherein the raised second hydrophobic region has a channel therein, the channel being in fluid flow communication with the first hydrophobic region surrounding each of the plurality of nozzle holes, and the channel being configured to transport fluid through the raised second hydrophobic region away from each of the plurality of nozzle holes. In other embodiments, the channel is wedge-shaped.

[0010] In some embodiments, a fluid ejection head is provided, the fluid ejection head comprising: a semiconductor substrate including a plurality of fluid ejectors on the semiconductor substrate; a flow feature layer attached to the semiconductor substrate; and a nozzle plate including a plurality of nozzle holes in the nozzle plate, the nozzle plate attached to the flow feature layer on the semiconductor substrate, wherein the nozzle plate comprises: a first hydrophobic region, the first hydrophobic region surrounding each of the plurality of nozzle holes, whereby the first hydrophobic region is configured to reduce overflow of the nozzle plate.

[0011] In other embodiments, a method for modifying a nozzle plate of a fluid ejection device to reduce fluid overflow on the nozzle plate is provided. The method includes: applying a sacrificial layer to an exposed surface of the nozzle plate, wherein the exposed surface of the nozzle plate is hydrophobic. Imaging and developing the sacrificial layer to provide a protective cap over each nozzle hole in the nozzle plate, wherein the protective cap has a diameter greater than the diameter of the nozzle hole covered by the protective cap. Treating the uncapped surface of the nozzle plate to provide an uncapped hydrophilic surface region of the nozzle plate. Removing the protective cap from each nozzle hole of the nozzle plate to provide a nozzle plate having a first hydrophobic region surrounding each nozzle hole and a hydrophilic region adjacent to the first hydrophobic region. In other embodiments, the sacrificial layer is a layer of positive photoresist material.

[0012] In some embodiments, a negative photoresist material is applied to the exposed surface of the nozzle plate and the negative photoresist material is imaged and developed to provide a raised second hydrophobic region above a hydrophilic region adjacent to a first hydrophobic region surrounding each nozzle hole. In other embodiments, a channel extending downward to the hydrophilic region is imaged and developed in the raised second hydrophobic region to direct fluid away from each nozzle hole.

[0013] The aforementioned embodiments provide a fluid ejection head in which a fluid boundary region and a fluid runoff region are present on the exposed surface of the nozzle plate to promote self-correction of overflowing nozzles and suppress cross-linked flooding of the nozzles by improving the retention or redirection of fluid that may accumulate on the surface of the nozzle plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a perspective view, not drawn to scale, of a fluid ejection device according to the present disclosure.

[0015] Figure 2 is a cross-sectional view, not drawn to scale, of a portion of an injection head according to the present disclosure.

[0016] Figures 3 to 6 is a cross-sectional view, not drawn to scale, of an injection head made according to the first embodiment of the present disclosure.

[0017] Figure 7 yes Figure 6 A not-to-scale plan view of the spray head is shown.

[0018] Figure 8 is a cross-sectional view, not drawn to scale, of a portion of an injection head made according to a second embodiment of the present disclosure.

[0019] Fig. 9 yes Figure 8 A not-to-scale plan view of the spray head is shown.

[0020] Fig.10 is a cross-sectional view, not to scale, of a finished injection head according to a second embodiment of the present disclosure.

[0021] Fig.11 yes Fig.10 A not-to-scale plan view of the spray head is shown.

[0022] Fig.12 The protective cover is removed Figure 8 A not-to-scale plan view of the spray head is shown.

[0023] Figure 13 to Figure 14 is a cross-sectional view, not drawn to scale, of an injection head made according to a third embodiment of the present disclosure.

[0024] Figure 15 to Figure 16 is used Fig.14 A not-to-scale plan view of an injection head according to a fourth embodiment of the present disclosure is shown.

[0025] Fig.17 is a cross-sectional view, not drawn to scale, of an injection head according to a fifth embodiment of the present disclosure.

[0026] Fig.18 is a cross-sectional view, not drawn to scale, of an injection head according to a sixth embodiment of the present disclosure.

[0027] [Description of symbols]:

[0028] 100: Nasal spray device

[0029] 102: Nozzle

[0030] 104: Main body

[0031] 106: Power button

[0032] 108: Power indicator LED

[0033] 110: Dose button

[0034] 112: Light Emitting Diode

[0035] 114: Fluid ejection head

[0036] 116: Semiconductor substrate

[0037] 118: Fluid Injector

[0038] 120: Fluid through hole

[0039] 122: Fluid chamber

[0040] 124: Flow feature layer

[0041] 126: Nozzle hole

[0042] 128: Nozzle plate

[0043] 130: Hydrophobic layer

[0044] 132: Sacrificial Layer

[0045] 134: Mask

[0046] 136: Opaque area

[0047] 138: Transparent area

[0048] 140: Arrow

[0049] 142: Protective cover

[0050] 144: Exposed Surface

[0051] 146: Arrow

[0052] 148: Hydrophilic Area

[0053] 150: Hydrophobic area

[0054] 152: Unshielded area / exposed nozzle plate surface / hydrophilic area

[0055] 154: Negative photoresist material / imaged negative photoresist layer

[0056] 156: Mask

[0057] 158: Opaque area

[0058] 160: Transparent area

[0059] 162: Drainage Dam

[0060] 170: Channel with a wedge shape

[0061] 172: Channel with rectangular shape

[0062] 174: Thick hydrophobic layer

[0063] 176: Hydrophobic Ridge

[0064] 178: Inner corner

[0065] 180: Outside corner

[0066] 184: Uncovered area / rough hydrophobic area

[0067] 186: Covered area / smooth hydrophobic area DETAILED DESCRIPTION

[0068] The present disclosure relates to improved fluid ejection heads, and more particularly to improvements associated with nozzle plates of fluid ejection heads for fluid dispensing devices. The fluid ejection heads may be used in a variety of fluid ejection devices, including but not limited to printers, and nasal spray devices 100 (100 for delivering medication to a patient) Figure 1 ), devices for depositing one or more fluids into the wells of a microplate or onto a glass slide, and similar devices. In devices such as the nasal spray device 100, a precise amount of medication must be delivered to a patient through a nozzle 102 using a fluid ejector head, wherein the fluid ejector head is attached to a fluid cartridge in the body 104 of the device. A power button 106 and a power indicator light emitting diode (LED) 108 are provided to indicate that the device is ready to start. The dose button 110 can be activated by the patient to deliver a specified dose of fluid from the ejector head as indicated by the light emitting diode 112. However, if the fluid accumulates on the ejector head, incorrect distribution of the medication may occur. This is particularly troublesome in such devices 100 where the fluid ejector head cannot be used for a horizontal, downward fluid ejection sequence. Such devices 100 generally do not include a wiper blade for removing excess fluid from the surface of the nozzle plate. Therefore, the improved nozzle plate and fluid ejector head described herein provide a means for reducing or preventing fluid from accumulating on the surface of the nozzle plate adjacent to the nozzle holes in the nozzle plate. The apparatus and methods described herein may also reduce or eliminate cross-contamination of fluids on a nozzle plate surface where the jet head is configured to jet a plurality of different fluids.

[0069] exist Figure 21. A portion of a fluid ejector head 114 is shown in FIG. The fluid ejector head 114 includes a semiconductor substrate 116 on which a fluid ejector 118 is disposed. The fluid ejector 118 may be a heater resistor or a piezoelectric device. Fluid is provided to the fluid ejector head from a fluid cartridge in the body 104 of the device through a fluid through hole 120 etched through the semiconductor substrate 116. The fluid then flows into a fluid chamber 122 in a flow feature layer 124, wherein the fluid ejector 118, when activated, causes the fluid to be discharged through a nozzle hole 126 in a nozzle plate 128. The uppermost layer of the nozzle plate 128 is a hydrophobic layer 130. Therefore, the hydrophobic layer 130 may include a hydrophobic agent, for example, heptadecafluorodecyltrimethoxysilane, octadecyldimethylchlorosilane, octadecyltrichlorosilane, methyltrimethoxysilane, octyltriethoxysilane, phenyltrimethoxysilane, tert-butylmethoxysilane, tetraethoxysilane, sodium methyl silicate, vinyltrimethoxysilane, N-(3-(trimethoxysilyl)propyl)ethylenediaminepolymethylmethoxysiloxane, polydimethylsiloxane, polyethylhydrogensiloxane, and dimethylsiloxane. The hydrophobic agent may be included in the hydrophobic layer 130, or the hydrophobic agent may be coated on the nozzle plate 128. The thickness of the hydrophobic layer 130 may be in the range of about 3 micrometers to about 10 micrometers.

[0070] In the first embodiment of the present disclosure, a sacrificial layer 132, such as a positive photoresist layer, may be spin coated or laminated to the hydrophobic layer 130 of the nozzle plate 128 / 130. Figure 3 As shown, a sacrificial layer 132 is applied to the hydrophobic layer 130. The thickness of the sacrificial layer is not particularly critical, as long as the sacrificial layer 132 has sufficient viscosity to span the nozzle hole 126. Therefore, the sacrificial layer can have a thickness ranging from about 5 microns to about 50 microns. Then, the sacrificial layer 132 can be imaged using actinic radiation (e.g., ultraviolet light) as shown by arrow 140 through a mask 134, which includes opaque areas 136 and transparent areas 138. After the exposed portions of the sacrificial layer 132 are developed, as shown in FIG. Figure 4 As shown, the protective cover 142 remains on the nozzle hole 126. As shown by arrow 146 ( Figure 5 ), the exposed surface 144 of the nozzle plate 128 / 130 is treated with oxygen plasma to change the surface energy of the exposed area to provide a hydrophilic region 148 to surround a capped hydrophobic region 150 of the nozzle plate, such as Figure 6 As shown in the cross-sectional view of Figure 7 As described above, the hydrophilic region may have the same thickness as the hydrophobic layer 130.

[0071] In the second embodiment, if Figure 8 to Figure 9As shown, the fluid ejection head 114 is formed by a hydrophobic layer 130 (see Figure 4 ) below the hydrophobic area 150 formed by the nozzle plate 128 having a hydrophilic property. Therefore, the exposed surface 144 (refer to Figure 5 ) can be subjected to bias, heating and highly selective radio frequency (RF) plasma etching, wherein the protective cover 142 shields each nozzle hole 126 (refer to Figure 2 ) and the unshielded region 152 of the nozzle plate is formed by removing the hydrophobic layer 130 (refer to Figure 5 ) and become hydrophilic, such as Figure 8 shown.

[0072] Other surface treatments may be used to increase the hydrophilicity of the exposed nozzle plate surface 152. For example, in addition to changing the surface energy of the exposed nozzle plate surface 152, a high bias plasma may be used on the surface to impart surface roughness through a sputtering effect. Roughening the surface may help improve adhesion to subsequently applied layers of material. Plasma etching is preferably used to create a permanent hydrophilic area on the surface 152 of the nozzle plate, while plasma treatment is typically used to improve adhesion to additional layers. Various gases, such as forming gas and oxygen, may be used in the process to change the surface chemistry of the exposed nozzle plate surface 152.

[0073] In the first and second embodiments, then, from the hydrophobic region 150 ( Fig.10 ) peeling off the protective cover 142 to provide the following nozzle plate, the nozzle plate having only: a hydrophobic area 150 surrounding each nozzle hole 126, and a hydrophilic area 148 surrounding the hydrophobic area 150 ( Fig.11 ) or hydrophilic region 152( Fig.12 ). Protective cap 142 may be stripped using a conventional photoresist solvent bath and high or low pressure rinse, or using a conventional deep reactive ion etch stripping process for photoresist materials.

[0074] In a third embodiment of the present disclosure, a negative photoresist material 154 is applied to the lift-off surface ( Fig.10 ) to cover the hydrophobic region 150 and the hydrophilic region 148, such as Fig.13As shown. The negative photoresist material has a thickness ranging from about 1 micron to about 5 microns, for example, about 1.5 microns to 2.5 microns. Using actinic radiation as described above (as shown by arrow 140), the negative photoresist material 154 is imaged through a mask 156 including opaque areas 158 and transparent areas 160. When the imaged negative photoresist layer 154 is developed, a hydrophobic levee 162 ( Fig.14 ) to inhibit overflow from spreading across the nozzle plate surface to the nozzle hole 126. In some embodiments, the negative photoresist material 154 is hydrophobic. In other embodiments, the negative photoresist material is hydrophilic.

[0075] In a fourth embodiment, the negative photoresist material 154 can be imaged and developed to form a channel extending downward to the hydrophilic region, the channel being adjacent to the hydrophobic region 150 around the nozzle hole 126 and promoting fluid flow away from the nozzle hole. In some embodiments, the channel 170 has a wedge shape in plan view, such as Fig.15 In other embodiments, the channel 172 has a rectangular shape in plan view, such as Fig.16 The rectangular shaped channel 172 can be made narrow enough to promote capillary action to push the fluid away from the nozzle hole 126. Various other channel geometries can also be used, as long as the channel is deep enough to extend from the exposed surface of the hydrophobic bank 162 downward to the hydrophilic area 148 below the hydrophobic bank 162.

[0076] In the fifth embodiment, as described above, the thick hydrophobic layer 174 applied to the nozzle plate 128 may be partially etched around the protective cover 142 to provide a hydrophobic ridge 176 around the nozzle hole 126, such as Fig.17 The thick hydrophobic layer can be greater than 5 microns thick, up to about 10 microns thick. The inner corner 178 of the hydrophobic ridge 176 serves as a first drop-pinning boundary, and the outer corner 180 of the hydrophobic ridge serves as a second drop-pinning boundary to prevent droplets from covering the nozzle orifice 126.

[0077] In the sixth embodiment, the Fig.17 The thick hydrophobic layer 174 shown is sputtered or etched so that Fig.18As shown, the hydrophobic surface is roughened but not completely removed in an uncapped region 184 surrounding a capped region 186. The aforementioned embodiments provide a nozzle plate having a smooth hydrophobic region 186 surrounding a nozzle hole 126 and a roughened hydrophobic region 184 surrounding the smooth hydrophobic region 186. Increasing the surface roughness of the nozzle plate is believed to reduce the wettability of some fluids, thereby acting as a micro-levee around the nozzle hole, based on capillary, gravitational and viscous effects, as well as the surface energy of the nozzle plate and the surface tension of the fluid.

[0078] In all of the above embodiments, the photoresist material can be deposited by spin coating, spray coating, or by lamination, and in some cases, lamination is the most practical. In the case of spin coating, the photoresist material must have sufficient viscosity and the casting rate must be high enough so that the photoresist layer covers the top of the nozzle hole 126.

[0079] The photoresist materials described in the embodiments herein include a photoacid generator and can be formulated to include one or more multifunctional epoxy compounds, difunctional epoxy compounds, relatively high molecular weight polyhydroxy ethers, adhesion enhancers, and aliphatic ketone solvents. For the purposes of this disclosure, "difunctional epoxy" means: epoxy compounds and materials with only two epoxy functional groups in the molecule. "Multifunctional epoxy" means: epoxy compounds and materials with more than two epoxy functional groups in the molecule.

[0080] The epoxy component used to make the photoresist formulation according to the present disclosure can be selected from aromatic epoxides, such as glycidyl ethers of polyphenols. An exemplary first multifunctional epoxy resin is a polyglycidyl ether of a novolac resin, for example, a novolac epoxy resin having an epoxide gram equivalent weight of about 190 to about 250 and a viscosity of about 10 centipoise to about 60 centipoise at 130°C.

[0081] The multifunctional epoxy component may have a weight average molecular weight of about 3,000 Daltons to about 5,000 Daltons as determined by gel permeation chromatography, and an average epoxy group functionality of greater than 3, preferably about 6 to about 10. The amount of multifunctional epoxy resin in the photoresist formulation may range from about 30 wt % to about 50 wt %, based on the weight of the dry photoresist layer.

[0082] The difunctional epoxy component may be selected from difunctional epoxy compounds including diglycidyl ether of bisphenol A, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexenecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexenecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate and bis(2,3-epoxycyclopentyl)ether.

[0083] An exemplary difunctional epoxy component is a bisphenol A / epichlorohydrin epoxy resin having an epoxide equivalent weight greater than about 1000. "Epoxide equivalent" refers to the number of grams of resin containing 1 gram equivalent of epoxide. The weight average molecular weight of the difunctional epoxy component is generally greater than 2500 Daltons, for example, from about 2800 to about 3500 Daltons. The amount of the first difunctional epoxy component in the photoresist formulation may range from about 30 weight % to about 50 weight %, based on the weight of the cured resin.

[0084] Exemplary photoacid generators include compounds or mixtures of compounds capable of generating cations, for example, aromatic complex salts selected from onium salts of Group VA elements, onium salts of Group VIA elements, and aromatic halonium salts. When exposed to ultraviolet radiation or electron beam radiation, the aromatic complex salts can generate an acid moiety that initiates a reaction with an epoxide. The photoacid generator can be present in the photoresist formulation described herein in an amount ranging from about 5% by weight to about 15% by weight based on the weight of the curing resin.

[0085] Compounds that generate proton acid when irradiated with active rays can be used as the photoacid generator, including, but not limited to, aromatic iodonium complex salts and aromatic sulfonium complex salts. Examples include: di-(tert-butylphenyl)iodonium trifluoromethanesulfonate, diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, [4-(octyloxy)phenyl]phenyliodonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, 4,4'-bis[diphenylsulfonium]diphenyl sulfide, bis-hexafluorophosphate, 4,4'-bis[bis([β]-hydroxyethoxy)phenylsulfonium]diphenyl sulfide, bis-hexafluoroantimonate, 4,4'-bis[bis([β]-hydroxyethoxy)phenylsulfonium]diphenyl sulfide-bis-hexafluorophosphate , 7-[di(p-tolyl)sulfonium]-2-isopropylthioxanthone hexafluorophosphate, 7-[di(p-tolyl)sulfonium]-2-isopropylthioxanthone hexafluoroantimonate, 7-[di(p-tolyl)sulfonium]-2-isopropyltetrakis(pentafluorophenyl)borate, phenylcarbonyl-4'-diphenylsulfonium diphenyl sulfide hexafluorophosphate, phenylcarbonyl-4'-diphenylsulfonium diphenyl sulfide hexafluoroantimonate, 4-tert-butylphenylcarbonyl-4'-diphenylsulfonium diphenyl sulfide hexafluorophosphate, 4-tert-butylphenylcarbonyl-4'-diphenylsulfonium diphenyl sulfide hexafluoroantimonate, 4-tert-butylphenylcarbonyl-4'-diphenylsulfonium diphenyl sulfide tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate and similar salts.

[0086] The hydrophobic agent that can be used in positive or negative photoresist materials includes silicon-containing materials, for example, silane and siloxane. Therefore, the hydrophobic agent can be selected from: heptafluoro-decyl trimethoxysilane, octadecyl dimethyl chlorosilane, octadecyl trichlorosilane, methyl trimethoxy silane, octyl triethoxy silane, phenyl trimethoxy silane, tert-butyl methoxy silane, tetraethoxy silane, sodium methyl silicate, vinyl trimethoxy silane, N-(3-(trimethoxysilyl) propyl) ethylenediamine polymethyl methoxy siloxane, polydimethyl siloxane, polyethyl hydrogen siloxane and dimethyl siloxane. Based on the gross weight of the cured resin, the amount of the hydrophobic agent in the cured photoresist material can be about 0.5 wt % to about 2 wt %, for example, about 1.0 wt % to about 1.5 wt %, including all ranges contained in the described range.

[0087] The solvent used to prepare the photoresist formulation is a non-photoreactive solvent. Non-photoreactive solvents include, but are not limited to, gamma-butyrolactone, C1 to C6 acetates, tetrahydrofuran, low molecular weight ketones, mixtures thereof, and similar solvents. The non-photoreactive solvent is present in the formulation mixture for providing the photoresist material in an amount ranging from about 20 wt % to about 90 wt %, for example, from about 40 wt % to about 60 wt %, based on the total weight of the photoresist formulation. The non-photoreactive solvent is generally not retained in the cured photoresist layer and is therefore removed before or during the curing step of the photoresist layer.

[0088] The photoresist formulation may optionally include an effective amount of an adhesion enhancer, such as a silane compound. Silane compounds that are compatible with the components of the photoresist formulation typically have a functional group that is capable of reacting with at least one component selected from the group consisting of a multifunctional epoxy compound, a difunctional epoxy compound, and a photoinitiator. Such an adhesion enhancer may be a silane having an epoxy functional group, such as 3-(guanidino)propyltrimethoxysilane and glycidoxyalkyltrialkoxysilane (e.g., γ-glycidoxypropyltrimethoxysilane). When used, the adhesion enhancer may be present in an amount ranging from about 0.5 wt % to about 2 wt %, such as from about 1.0 wt % to about 1.5 wt %, based on the total weight of the cured resin, including all ranges contained therein. As used herein, an adhesion enhancer is defined to mean an organic material that is soluble in the photoresist composition and contributes to the film-forming and adhesion properties of the photoresist layer.

[0089] For the purposes of this specification and the appended claims, unless otherwise indicated, all numerals expressing quantities, percentages or ratios and other numerical values ​​used in the specification and claims should be understood as being modified in all cases by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth in the above specification and the appended claims are approximate values ​​that may vary depending on the desired properties sought to be obtained by the present disclosure. At the very least, each numerical parameter should at least be interpreted in light of the number of reported significant digits and by applying ordinary rounding techniques, and no attempt is made to limit the application of the doctrine of equivalents to the scope of the claims.

[0090] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseeable or may not be foreseeable may occur to the applicant or other skilled in the art. Therefore, the appended claims of the application as filed and as they may be amended are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. A nozzle plate configured for use in a fluid ejection head, characterized in that: The nozzle plate includes a plurality of nozzle holes, The nozzle plate is attached to a flow feature layer on a semiconductor substrate, wherein The nozzle plate also includes a first hydrophobic region surrounding each of the plurality of nozzle holes.

2. The nozzle plate according to claim 1, characterized in that Also includes: a second hydrophobic layer disposed on the exposed surface of the nozzle plate, and in, The second hydrophobic layer includes a hydrophobic region that is raised relative to the first hydrophobic region.

3. The nozzle plate according to claim 1, characterized in that Also includes: A hydrophilic region adjacent to the first hydrophobic region.

4. The nozzle plate according to claim 3, characterized in that Also includes: a raised second hydrophobic region located above the hydrophilic region, in, The second hydrophobic region of the protrusion includes a channel, The channel is in fluid flow communication with the first hydrophobic region surrounding each of the plurality of nozzle orifices, and The channel is configured to deliver fluid through the second hydrophobic region of the projection away from each of the plurality of nozzle holes.

5. The nozzle plate according to claim 4, characterized in that The channel is wedge-shaped.

6. A fluid ejection head, characterized in that: include: The nozzle plate of claim 1.

7. A fluid ejection head, characterized in that: include: a semiconductor substrate comprising a plurality of fluid ejectors on the semiconductor substrate; a flow feature layer attached to the semiconductor substrate; as well as a nozzle plate including a plurality of nozzle holes in the nozzle plate, the nozzle plate being attached to the flow feature layer on the semiconductor substrate, The nozzle plate includes a first hydrophobic region, wherein the first hydrophobic region surrounds each of the plurality of nozzle holes.

8. The fluid ejection head according to claim 7, wherein: The nozzle plate further includes: a second hydrophobic layer disposed on an exposed surface of the nozzle plate, and in, The second hydrophobic layer includes a hydrophobic region that is raised relative to the first hydrophobic region.

9. The fluid ejection head according to claim 7, wherein: Also includes: A hydrophilic region adjacent to the first hydrophobic region.

10. The fluid ejection head according to claim 9, wherein: Also includes: a raised second hydrophobic region located above the hydrophilic region, in, The second hydrophobic region of the protrusion includes a channel, The channel is in fluid flow communication with the first hydrophobic region surrounding each of the plurality of nozzle orifices, and The channel is configured to deliver fluid through the second hydrophobic region of the projection away from each of the plurality of nozzle holes.

11. The fluid ejection head according to claim 10, wherein: The channel is wedge-shaped.

12. A fluid ejection device, characterized in that: include: A fluid ejection head as claimed in claim 7.

13. A method for improving a nozzle plate of a fluid ejection device to reduce fluid overflow on the nozzle plate, characterized in that: The method comprises: applying a sacrificial layer to an exposed surface of the nozzle plate, wherein the exposed surface of the nozzle plate is hydrophobic; imaging and developing the sacrificial layer to provide a protective cap over each nozzle hole in the nozzle plate, wherein the protective cap has a diameter greater than a diameter of the nozzle hole covered by the protective cap; treating the uncovered surface of the nozzle plate to provide an uncovered hydrophilic surface area of ​​the nozzle plate; and The protective cover is removed from each of the nozzle holes of the nozzle plate to provide a nozzle plate having a first hydrophobic region surrounding each of the nozzle holes and a hydrophilic region adjacent to the first hydrophobic region.

14. The method according to claim 13, characterized in that The sacrificial layer includes: a positive photoresist material layer.

15. The method according to claim 13, characterized in that Also includes: A negative photoresist material is applied to the exposed surface of the nozzle plate.

16. The method according to claim 15, characterized in that Also includes: The negative photoresist material is imaged and developed to provide a raised second hydrophobic region above the hydrophilic region adjacent to the first hydrophobic region surrounding each of the nozzle orifices.

17. The method according to claim 16, characterized in that Also includes: A channel extending downwardly to the hydrophilic region is imaged and developed in the raised second hydrophobic region to direct fluid away from each of the nozzle orifices.

18. The method according to claim 17, characterized in that The channel is wedge-shaped.

Images