Hybrid thin film stack for fluid path protection

Abstract

A fluid ejection device includes a fluid ejection die comprising a fluid feed hole, a fluid distribution body including a fluid distribution channel to deliver fluid to the fluid feed hole, a dielectric coating over the fluid feed hole, and a metallic coating over the fluid distribution channel and the dielectric coating.

Description

HYBRID THIN FILM STACK FOR FLUID PATH PROTECTIONBACKGROUND

[0001] Fluidic dies refer to structures through which fluid may move through channels in a layer or layers of a material or a stack of materials. In the context of integrated circuits, a die refers to a block of semiconducting material comprising circuity components, a fluidic die may include fluidic, mechanical, and / or circuitry components. In the context of printing, one type of fluidic die includes fluid ejection dies. Fluid ejection dies may include small channels that carry fluid, such as ink, to ejection chambers, where the fluid is ejected from the die. The die may be molded into or otherwise coupled to a fluid distribution body, which delivers the fluid to the die. There may be other types of fluidic dies. For instance, and without limitation, in the context of lab-on-a-chip, a fluidic die may include circuitry and / or fluidic elements for mixing and separating, fluidic logic blocks, assays, and the like.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 A is a cross-sectional side view of an example fluid flow structure.

[0003] FIG. IB is a cross-sectional end view of the fluid flow structure of FIG. 1 A.

[0004] FIG. 2 is a cross-sectional view of a fluid ejection die.

[0005] FIG. 3 is a cross-sectional view of an example of a fluid flow structure.

[0006] FIG. 4 is a diagram of an example of a method of manufacturing a fluid flow structure.

[0007] FIGS. 5A-5C are examples of metallic coating layers on a fluid distribution body.

[0008] FIGS. 6A-6D are examples of coating layers on a fluid feed hole of a fluid ejection die.

[0009] FIG. 7 is a cross-sectional view of an example of a fluid ejection die being molded.

[0010] FIGS. 8A-8C are examples of fluid distribution bodies with different surface topographies.DETAILED DESCRIPTION[00111 Fluidic dies may be molded or otherwise coupled to a fluid distribution body to form a complete fluid flow structure. The fluid distribution body may have channels to deliver fluid to portions of the fluidic die. The fluid distribution body may be made of a layer or layers of molding material, such as epoxy mold compound. The fluidic die may be placed into a mold, and molding material may be poured or injected into the mold to form the fluid flow structure. The mold may include channel mold inserts or other raised features that form a negative of a channel or channels. When the molding material sets and the fluid flow structure is removed from the mold, the fluid distribution body is bonded to the fluidic die, with the channel or channels formed in the fluid distribution body.

[0012] As discussed above, the fluidic die may include circuitry and / or fluidic elements for mixing and separating, fluidic logic blocks, assays, and the like. In some examples, the fluidic die may be a fluid ejection die that ejects fluid from the fluid flow structure. For example, an inkjet printer may include fluid ejection dies (e.g., die slivers) that heat ink to eject the ink from an ejection nozzle onto a surface or substrate, such as paper. Each fluid ejection die may include ink feed holes that deliver ink to ejection chambers, each of which includes an ejection nozzle. The fluid ejection die may include circuitry that can deliver an electrical current to a resistor in each ejection chamber. The electrical current can heat the resistor, vaporizing some of the ink in the fluid ejection chamber and forcing ink out of the respective ejection nozzle. In some examples, the fluidic die may be a fluid ejection die used to eject particles of interest (e.g., cells, chemical samples, etc.) that can be dispensed into wells on a well plate for digital titration. In still other examples, the fluidic die may be a microelectromechanical system (MEMS device) that receives and analyzes or distributes fluid.

[0013] Referring now to FIGS. 1 A and IB, a cross-sectional side view and a cross-sectional end view of a fluid flow structure 10 are respectively shown, according to some examples. It should be understood that the figures are not to scale, and the sizes of several components have been enlarged for clarity. The fluid flow structure 10 may include a fluidic die 12. The fluidic die 12 of FIGS. 1 A and IB is shown as a fluid ejection die, for example, an ink ejection die for an inkjet printer. However, it should be understood that other types of fluidic dies 12,such as labs-on-a-chip or other MEMS devices may be similarly embedded into a fluid flow structure 10. The fluidic die 12 may be an elongated sliver with a length more than three times its width. As used herein, “length” refers to a distance along a horizontal axis as shown in FIG. 1 A (e.g., along a longitudinal axis of the fluidic die 12), “width” refers to a distance along a horizontal axis as shown in FIG. IB, and thickness refers to a length along a vertical axis as shown in FIG. 1A or FIG. IB, unless otherwise specified. In some examples, the fluidic die 12 may include a substrate 14, which may be made of silicon, and an ejection layer 16. As discussed above, the fluidic die 12 may be molded into or otherwise coupled to a fluid distribution body 18. The fluid distribution body 18 may include a fluid distribution channel 20 (e.g., a slot) that is fluidly coupled with fluid feed holes 22 in the substrate 14. The fluid feed holes 22 extend through the substrate 14 and are further fluidly coupled with the ejection chambers 24 in the ejection layer 16. Fluid may be supplied to the fluid distribution channel 20 and may travel through the fluid feed holes 22 to the ejection chambers 24. When an electrical current is supplied to a resistor 27 positioned near the top of an ejection chamber 24, the resistor may rapidly heat up, causing fluid to be ejected from a nozzle 26 that is fluidly coupled with the ejection chamber 24. The ejection layer 16 may include bond pads 28 at each end to form electrical connections with electrical terminals of a control device, such as an inkj et printer body. The fluid flow structure 10 may be referred to as a fluid ej ection device when the fluidic die 12 is a fluid ejection die, such as an ink ejection die for an inkjet printer.[0014| In some examples, the fluid distributed by the fluid distribution body 18 and ejected by the fluidic die 12 may etch (e.g., corrode) the silicon substrate 14 due to the chemical makeup of the fluid. For example, highly basic fluids (e.g., with pH above 10) may etch silicon. In inkjet printers, the etching or corrosion caused by certain types of inks may be referred to as “ink attack.” Over time, the silicon substrate 14 may be etched to the point that the structural integrity of the fluidic path is compromised, which can lead to electrical failures requiring the replacement of the fluid flow structure 10. Further, the silicon that is etched away may mix with the fluid, which may clog the nozzles 26 of the fluidic die 12. Accordingly, there may be a desire to provide a coating to the silicon substrate 14 and other components of the fluid flow structure to protect the components from etching or corrosion due to chemical reactions with the fluid.

[0015] In some examples, dielectric passivation may be used to coat the entire fluid flow structure 10 after the fluidic die 12 is bonded to the fluid distribution body 18. For example, atomic layer deposition or plasma-enhanced chemical vapor deposition may be used to coat the fluid flow structure 10 with a thin layer of hafnium oxide. The atomic layer deposition process may include reacting a hafnium precursor with water vapor in pulses under high temperature and vacuum conditions. The hafnium precursors are highly sensitive to contamination if other gases are present during the process. The fluid distribution body 18, which may be made from an organic epoxy mold compound, may release (e.g., off-gas) volatile organic components under the high temperature and vacuum conditions that can react with the precursors. These reactions may impact the properties and quality of the hafnium oxide film deposited in the fluid flow structure 10. Further, due to the mismatch of thermal expansion coefficients between the fluid distribution body 18 and a layer of dielectric material like hafnium oxide, the dielectric layer may be prone to flaking off of the fluid distribution body 18.[0(H6| Using atomic layer deposition of dielectric material on the entire fluid flow structure 10 may cause other undesirable effects. For example, because atomic layer deposition can result in every surface exposed to the precursors being coated, the ejection layer 16 (e.g., the bore layer) may also be coated with the dielectric material. The dielectric film may be hydrophilic, with a contact angle of less than 15 degrees. The hydrophilic film on the ejection layer 16 may cause fluid puddling, which may result in ejection trajectory errors. In inkjet printers, these trajectory errors may reduce print quality. The hydrophilic film on the ejection layer 16 may also cause air ingestion into the nozzles 26, which may further degrade image quality in inkjet printers.

[0017] In other examples, directional (e.g., line-of-sight) deposition of metals such as tantalum or titanium may be used to coat the fluid flow structure 10. For example, sputter deposition (e.g., sputtering) or electron-beam evaporation (e.g., e-beam evaporation, electronbeam physical vapor deposition, etc.) of metal coatings may be used. However, as shown in FIG. 2, the process of forming the fluidic die 12 and the fluid feed holes 22 may result in an undercut 23 in the silicon substrate 14, at the interface of the substrate 14 and the ejection layer 16. It may be difficult to fully coat the undercut 23 using directional metal deposition,and a gap in the coating near the undercut 23 could cause etching of the fluidic die 12 in the area of the undercut 23, which may undermine the structural integrity of the fluidic die 12.

[0018] FIG. 3 shows an example of a fluid flow structure 100, and FIG. 4 shows an example of a method 200 of manufacturing the fluid flow structure 100. The fluid flow structure 100 may be substantially similar to the fluid flow structure 10, except as shown and described herein. At operation 202 of the method 200, a dielectric material may be deposited onto a wafer of silicon substrates 14 for fluidic dies 12. The wafer may include, for example, hundreds or thousands of silicon substrates 14 formed of a single piece of silicon. The dielectric material may be deposited using a passivation process such as atomic layer deposition. The dielectric material may be, for example, an oxide, nitride, or carbide of titanium, hafnium, aluminum, silicon, chromium, or tungsten (e.g., HfCh, SiCh, AI2O3, ZrCb CnCh, TaN, WN, W2N, WN2, SiC, or TaC). During the process of depositing the dielectric material, substantially every exposed surface of the wafer, including the fluid feed holes 22 and the top and bottom surfaces of the wafer may be coated in the dielectric material. In some examples, operation 202 may be repeated to deposit a second layer of dielectric material, which may be the same dielectric material as or a different dielectric material than the first layer. At operation 204 of the method 200, a portion of the dielectric material may be removed from one side of the wafer, for example, in locations where bond pads will be coupled to the silicon substrates 14. The portion of the dielectric material may be removed, for example using a machining or ablation operation (e.g., powder blasting, etching, lasering, milling, drilling, electrical discharge machining). At operation 206, an ejection layer 16 may be formed on one side of each silicon substrate 14 on top of the layer of dielectric material. The ejection layer may be made of SU8 or another type of negative photoresist and may define the ejection chambers 24 and nozzles. At operation 208 of the method 200, the wafer may be singulated into a plurality of separate fluidic dies 12. This, again, may be performed, for example using a machining or ablation operation (e.g., saw dicing, plasma dicing, stealth dicing, laser cutting, etc.) to cut each individual fluidic die from the wafer.|0019[ At operation 210 of the method 200, a fluidic die 12 may be molded or otherwise coupled to a fluid distribution body 18. The molding process can be, for example, a compression molding process or a transfer molding process that yields a molded fluidic die. The first side 104 of the fluidic die 12, to which the bond pads and ejection layer 16 arecoupled, may remain exposed and uncovered by the material (e.g., epoxy mold compound) of the fluid distribution body 18. The edges 106 and opposite side 108 of the fluidic die may be surrounded by the material of the fluid distribution body 18, which may not yet include the fluid distribution channel 20. The edges 106 of the fluidic die 12 may not include a layer of dielectric material, as the edges 106 may not have been exposed during the coating process before the wafer was singulated, exposing the edges 106. The second side 108 may include a coating of the dielectric material. At operation 212 of the method 200, the fluid distribution channel 20 may be cut or otherwise formed into the fluid distribution body 18 using, for example, a machining or ablation process (e.g., powder blasting, etching, lasering, milling, drilling, electrical discharge machining). The fluid distribution channel 20 may be cut to a depth at which a portion of the second side 108 of the fluidic die 12 is removed, to ensure that no material of the fluid distribution body 18 remains between the fluid distribution channel 20 and the fluid feed holes 22. This process may also remove the dielectric material from the second side 108 of the fluidic die 12 in the region of the second side 108 that is in fluid communication with the fluid distribution channel 20. The fluid feed holes 22 may remain coated in the dielectric material. In some examples, the mold used to form the fluid distribution body 18 may include a negative of the fluid channel, so that the fluid channels 20 are formed in operation 210, and operation 212 may not be performed. In these examples, the dielectric material may remain on the second side 108 of the fluidic die 12. In some examples, operation 210 may include molding multiple fluidic dies 12 (e.g., hundreds, thousands, etc.) into a single panel of material from which fluid distribution bodies 18 may be formed, and operation 212 may include forming fluid channels 20 for the multiple fluid distribution bodies 18.[0020| At operation 214 of the method 200, the surfaces of the fluid distribution body 18 may be roughened. This may improve the adhesion of the metallic coating applied in operation 214. In some examples, operation 214 may be performed using an etching process. In some examples, for example, when the mold used to form the fluid distribution body 18 includes a negative of the fluid distribution channel 20, release film positioned between the mold and the fluid distribution body 18 material may have a surface roughness that transfers to the fluid distribution body 18 during the molding process. At operation 216 of the method 200, the molded fluidic die (or dies in the panel), including the fluid distribution body 18 and fluidic die 12, may be coated in a metallic material. The metallic coating material may be, forexample, tantalum, titanium, gold, or tungsten. The metallic coating may be applied, for example, with a directional deposition method such as. The metallic coating may be applied from the side of the fluid distribution body 18 including the fluid distribution channel 20, such that the fluid distribution channel 20 and fluid feed holes 22 are coated in the metallic coating. The first side 104 of the fluidic die 12 may not be substantially coated in the metallic coating. In some examples, operation 214 may be repeated to deposit a second layer of metallic coating material, which may be the same metallic coating material as or a different metallic coating material than the first layer. At operation 218 of the method 200, the panel of molded fluidic dies may be singulated into fluid flow structures 10, for example, using a machining or ablation process (e.g., saw dicing, plasma dicing, stealth dicing, laser cutting, etc.).

[0021] The fluid flow structure 100 resulting from the method 200, as shown in FIG. 3, may include a dielectric material layer 110 coating the fluid feed holes 22, and, in some examples, a portion of the first side 104 of the fluidic die 12. The fluid flow structure 100 may further include a metallic coating layer 112 coating the fluid distribution channel 20, the second surface 108 of the fluidic die 12, and the portion 111 of the dielectric material layer 110 coating the fluid feed holes 22. FIGS. 5A-5C show examples of metallic coating layers 112 present on the fluid distribution body 18. In FIG. 5 A, the metallic coating layer 112 includes a single layer of tantalum 113 applied directly to the fluid distribution body 18. The single layer of tantalum 113 may be approximately 100 nanometers thick (e.g., between about 80 nanometers and about 120 nanometers thick, or between about 30 nanometers and about 170 nanometers thick). In FIG. 5B, the metallic coating layer 112 includes a first layer of titanium 114 applied directly to the fluid distribution body 18. The metallic coating layer 112 may include a second layer of tantalum 115, which may be applied on top of the first layer of titanium 114. The first layer of titanium 114 may be approximately 10 nanometers thick (e.g., between about 5 nanometers and about 15 nanometers thick, or between about 1 nanometer and about 20 nanometers thick). The second layer of tantalum 115 may be approximately 40 nanometers thick (e.g., between about 30 nanometers and about 50 nanometers thick, or between about 10 nanometers and about 70 nanometers thick). In FIG. 5C, the metallic coating layer 112 includes a single layer of tantalum 116 applied directly to the fluid distribution body 18. The single layer of tantalum 116 may be approximately 50 nanometersthick (e.g., between about 40 nanometers and about 60 nanometers thick, or between about 20 nanometers and about 80 nanometers thick).

[0022] FIGS. 6A-6D show examples of the coating layers that may be applied to the fluid feed holes 22 through the silicon substrate 14 of the fluidic die 12. In the example shown in FIG. 6A, the coatings include a dielectric material layer 110 made of a single layer of hafnium oxide 117 applied directly to the fluid feed holes 22. The hafnium oxide layer 117 may be approximately 10 nanometers thick (e.g., between about 5 nanometers and about 15 nanometers thick, between about 1 nanometer and about 20 nanometers thick). The coatings may also include a metallic coating layer 112 including a first layer of titanium 118, which may be applied on top of the hafnium oxide layer 117. The metallic coating layer 112 may also include a second layer of tantalum 119 which may be applied on top of the first layer of titanium 118. The first layer of titanium 118 may be approximately 10 nanometers thick (e.g., between about 5 nanometers and about 15 nanometers thick, or between about 1 nanometer and about 20 nanometers thick). The second layer of tantalum 119 may be approximately 50 nanometers thick (e.g., between about 40 nanometers and about 60 nanometers thick, or between about 10 nanometers and about 70 nanometers thick).

[0023] In the example shown in FIG. 6B, the coatings include a dielectric material layer 110 made of a single layer of hafnium oxide 120 applied directly to the fluid feed holes 22. The hafnium oxide layer 120 may be approximately 5 nanometers thick (e.g., between about 1 nanometer and about 15 nanometers thick, or between about 1 nanometer and about 20 nanometers thick). The coatings shown in FIG. 6B may also include a metallic coating layer 112 including a single layer of tantalum 121, which may be applied on top of the hafnium oxide layer 120. The single layer of tantalum 121 may be approximately 40 nanometers thick (e.g., between about 30 nanometers and about 50 nanometers thick, or between about 20 nanometers and about 80 nanometers thick). In the example shown in FIG. 6C the coatings include a dielectric material layer 110 made of a single layer of silicon carbide 122 applied directly to the fluid feed holes 22. The silicon carbide layer 122 may be approximately 5 nanometers thick (e.g., between about 1 nanometer and about 15 nanometers thick, or between about 1 nanometer and about 20 nanometers thick). The coatings shown in FIG. 6C may also include a metallic coating layer 112 including a single layer of tantalum 123, which may be applied on top of the silicon carbide layer 122. The single layer of tantalum 123 maybe approximately 55 nanometers thick (e.g., between about 45 nanometers and about 55 nanometers thick, or between about 20 nanometers and about 120 nanometers thick).(0024] In the example shown in FIG. 6D, the coatings include a dielectric material layer 110 made of a single layer of aluminum oxide 124 applied directly to the fluid feed holes 22. The aluminum oxide layer 124 may be approximately 2 nanometers thick (e.g., between about 1 nanometer and about 10 nanometers thick). The coatings may also include a metallic coating layer 112 including a first layer of titanium 125, which may be applied on top of aluminum oxide layer 124. The metallic coating layer 112 may also include a second layer of tantalum 126 which may be applied on top of the first layer of titanium 125. The first layer of titanium 125 may be approximately 15 nanometers thick (e.g., between about 10 nanometers and about 20 nanometers thick, or between about 1 nanometer and about 30 nanometers thick). The second layer of tantalum 126 may be approximately 30 nanometers thick (e.g., between about 20 nanometers and about 50 nanometers thick, or between about 10 nanometers and about 70 nanometers thick). In each example, the thickness or thicknesses of the layer or layers of metallic coatings in the metallic coating layer 112 on the fluid distribution body 18 may be the same or may be different from the thickness or thicknesses of the layer or layers of metallic coatings in the metallic coating layer 112 on the fluid feed holes 22. The thicknesses may vary based on the geometry of the fluid flow structure 10, with less material reaching the fluid feed holes 22 than the fluid distribution body 18 and / or based on the way the metallic coating materials are applied.

[0025] As discussed above, increased surface roughness of the fluid distribution body 18, which may be made of an organic epoxy mold compound, may improve adhesion of the metallic layer 110. The epoxy mold compound may have a low surface energy that impedes adhesion to a smooth surface. Off-gassing from the epoxy mold compound during deposition may further impede adhesion. By increasing the surface roughness, the metal atoms in the metallic layer 110 may be interlocked in the epoxy mold compound, improving the bond therebetween. The increased surface roughness also increases the surface area of the epoxy mold compound, providing more area for the metal atoms to bond to the fluid distribution body 18. Surface roughness (e.g., arithmetic mean roughness) can be controlled between about 0.1 micrometers to about 5 micrometers using textured release films during molding or using a plasma treatment (e.g., plasma etching). FIG. 7 shows an example of a fluiddistribution body 18 being molded using an upper mold 702. The upper mold 702 includes a channel negative 704 that forms the shape of the fluid distribution channel 20. A release film 706 may be positioned between the fluid distribution body 18 and the upper mold 702 to prevent the fluid distribution body 18 from sticking to the upper mold 702. Various release films 706 may have different surface textures and thicknesses, such that the surface roughness of the fluid distribution body 18 can be controlled based on the specific release film 706 used. Test results showed that a fluid distribution body 18 with a smooth surface finish experienced buckling of a tantalum metallic layer 110 and contamination of the ink in the fluid distribution channel 20. In contrast, a fluid distribution body 18 with a roughened surface finish had good adhesion of the tantalum metallic layer 110 and no ink contamination.[0026| The surface topography (e.g., roughness) of the epoxy mold compound in the fluid distribution body 18 can also be controlled using plasma etching or laser ablation. The epoxy mold compound used to form the fluid distribution body 18 may include silica filler in the form of grains or a powder mixed into a resin. After the fluid distribution body is molded, some of the resin in the epoxy mold compound or some of the silica can be removed to adjust the surface topography of the fluid distribution body 18.

[0027] Referring now to FIGS. 8A-8C, three examples of fluid distribution bodies 18 are shown with different surface topographies. In FIG. 8B, an example of a default topography after molding the fluid distribution body 18 using silica particles 802 mixed into a resin 804 is shown. As shown in FIG. 8B, the upper surfaces 806 and the surfaces of fluid distribution channel 20 are smooth. In FIG. 8A, an example of a silica-etched fast topography is shown. After molding the fluid distribution body 18 using silica particles 802 mixed into a resin 804 (e.g., similar to FIG. 8B), dry etching (e.g., plasma dry etching or reactive ion etching) or laser ablation may be used to remove portions of the exposed silica particles 802. For example, CHxFy (e.g., CHF3) gas may be used to etch SiCh (silica) to create the silica-etched fast topography. Argon gas may be used to clean and activate the surface for bonding. This creates small indentations 808 in the upper surfaces 806 and the surfaces of fluid distribution channel 20 that can be filled with metal atoms when the metallic layer 110 is applied. This may improve the adhesion of the metallic layer, similar to the surface roughening discussed above.

[0028] In FIG. 8C, an example of a resin-etched fast topography is shown. After molding the fluid distribution body 18 using silica particles 802 mixed into a resin 804 (e.g., similar to FIG. 8B), dry etching or laser ablation may be used to remove an outer layer of the resin 804 on the upper surfaces 806 and the surfaces of fluid distribution channel 20. For example, oxygen plasma may be used to etch polymers, such as the resin 804 in the epoxy mold compound, faster than the silica particles 802, creating the resin-etched fast topography. This further exposes the surfaces of the silica particles 802 and increases the surface area of the upper surfaces 806 and the fluid distribution channel 20 and may improve the adhesion of the metallic layer, similar to the surface roughening and silica-etched fast process discussed above. It should be understood that the silica particles 802 and the resin 804 shown in FIGS. 8A-8C are not to scale.

[0029] It should be noted that certain passages of this disclosure may reference terms such as “first” and “second” in connection with devices, surfaces or sides of devices, modes of operation, transmit chains, antennas, etc., for purposes of identifying or differentiating one from another or from others. These terms are not intended to merely relate entities (e.g., a first device and a second device) temporally or according to a sequence, although in some cases, these entities may include such a relationship. Nor do these terms limit the number of possible entities (e.g., devices) that may operate within a system or environment.10030] The term “a portion of’ as used herein represents an amount of a whole that comprises an amount of the whole that may be less than the whole or may include the whole, except as otherwise noted. For example, “a portion of’ may refer to an amount greater than 0 percent of the whole, up to and including 100 percent of the whole.

[0031] While this specification contains specific implementation details, these should not be construed as limitations on the scope of what may be claimed but rather as descriptions of features specific to particular implementations. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features may be described as acting in certain combinations and even initially claimed as such, features from a claimedcombination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

[0032] As utilized herein with respect to structural features (e.g., to describe shape, size, orientation, direction, relative position, etc.), the terms “approximately,” “about,” “substantially,” and similar terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.[0033| The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0034] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other examples, and that such variations are intended to be encompassed by the present disclosure.

[0035] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular tothe plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0036] The foregoing description of illustrative examples has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible considering the above teachings or may be acquired from practice of the disclosed examples. It is intended that the scope of the claimed subject matter be defined by the claims appended hereto and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A fluid ejection device comprising: a fluid ejection die comprising a fluid feed hole; a fluid distribution body comprising a fluid distribution channel to deliver fluid to the fluid feed hole; a dielectric coating over the fluid feed hole; and a metallic coating over the fluid distribution channel and the dielectric coating.

2. The fluid ejection device of claim 1, wherein the fluid ejection die comprises a silicon substrate and an ejection layer comprising a nozzle and a resistor to heat fluid to eject fluid from the nozzle, the silicon substrate comprising the fluid feed hole, and wherein the fluid distribution body is made of an epoxy mold compound.

3. The fluid ejection device of claim 1, wherein the metallic coating comprises one of tantalum, titanium, gold, or tungsten.

4. The fluid ejection device of claim 1, wherein the dielectric coating comprises an oxide, nitride, or carbide of titanium, hafnium, aluminum, silicon, chromium, or tungsten.

5. The fluid ejection device of claim 1, wherein the dielectric coating comprises hafnium oxide and the metallic coating comprises tantalum.

6. The fluid ejection device of claim 1, wherein the metallic coating comprises a first layer comprising a first metal and a second layer comprising a second metal different from the first metal.

7. A method of manufacturing a fluid ejection device, the method comprising: coating a fluid feed hole of a fluid ejection die with a dielectric material; molding the fluid ejection die into a fluid distribution body comprising a fluiddistribution channel to form a molded fluid ejection die with the fluid distribution channel in fluid communication with the fluid feed hole; and coating the fluid distribution channel and the fluid feed hole of the molded fluid ejection die with a metallic material.

8. The method of claim 7, wherein molding the fluid ejection die into the fluid distribution body comprises pouring an epoxy mold compound into a mold comprising a release film, the release film having a surface texture such that the fluid distribution body has an arithmetic mean surface roughness between about 0.1 micrometers and about 5 micrometers.

9. The method of claim 7, wherein the fluid distribution body comprises silica mixed with a resin, the method further comprising removing a portion of the resin or the silica from a surface of the fluid distribution body using laser ablation or dry etching to increase the surface area of the fluid distribution body.

10. The method of claim 7, further comprising forming an ejection layer on a side of the fluid ejection die after coating the fluid feed hole with the dielectric material.

11. The method of claim 7, wherein atomic layer deposition or plasma-enhanced chemical vapor deposition is used to coat the fluid feed hole.

12. The method of claim 7, wherein coating the fluid feed hole with the metallic material comprises coating the dielectric material in the fluid feed hole with the metallic material.

13. A method of manufacturing fluid ejection devices, the method comprising: coating, with a dielectric material, fluid feed holes of a plurality of fluid ejection dies formed into a wafer; singulating the plurality of fluid ejection dies;molding the plurality of fluid ejection dies into a panel of fluid distribution bodies comprising fluid distribution channels to form molded fluid ejection dies with a fluid distribution channel in fluid communication with a fluid feed hole; coating the fluid distribution channels and the fluid feed holes of the molded fluid ejection dies with a metallic material; and singulating the molded fluid ejection dies.

14. The method of claim 13, wherein coating the fluid feed holes with the dielectric material comprises coating substantially all of the wafer with the dielectric material using atomic layer deposition or plasma-enhanced chemical vapor deposition.

15. The method of claim 13, wherein molding the plurality of fluid ejection dies into the panel of fluid distribution bodies comprises pouring an epoxy mold compound into a mold comprising a release film, the release film having a surface texture such that the panel of fluid distribution bodies has an arithmetic mean surface roughness between about 0.1 micrometers and about 5 micrometers.

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