TW200836932A - Method of fabricating printhead having hydrophobic ink ejection face - Google Patents

Abstract

A method of fabricating a printhead having a hydrophobic ink ejection face is provided. The method comprises the steps of: (a) providing a partially-fabricated printhead comprising a plurality of nozzle chambers and a relatively hydrophilic nozzle surface, the nozzle surface at least partially defining the ink ejection face; (b) depositing a layer of relatively hydrophobic polymeric material onto the nozzle surface, the polymeric material being resistant to removal by ashing; and (c) defining a plurality of nozzle openings in the nozzle surface, thereby providing a printhead having a relatively hydrophobic ink ejection face. Steps (b) and (c) may be performed in any order.

Description

200836932 (1) Description of the Invention [Technical Field of the Invention] The present invention relates to the field of a printer. The present invention has been primarily developed to improve high resolution print reliability. [Prior Art] Many different types of prints have been developed. Print types are still in use today. Conventional printing to record on the printing medium with relevant recording media including offset printing, laser printing and copying printers, thermal paper printers, film recorders, sublimation printing Both the watch machine and the inkjet printer are on demand and continuous flow printers. When, quality, knot and operation are simple, each has its advantages and problems. In recent years, the field of inkjet printing (i.e., each or more ink nozzles have been driven out) has become increasingly popular due to its convenience. In the field of many different technologies on inkjet printing, reference is made to a document by J Moore at the "Non-Impact Printing Historical Perspective" published by Devices (edited in 1988 by R Dubeck and S Sherr). In particular, the quality of printing in inkjet print heads, and a large number of these forms have various methods. Generally used for column printing, dot matrix impact thermal transfer printing machine, is ready to print (drop to cost, speed seed printers have their own ink pixels are suitable and multifunctional The essence of this was invented. In the review of this Output Hard Copy: Introduction and Edition pp. 207-220, 200836932 (2) The inkjet printer itself has many different forms. A continuous ink flow through the inkjet printing device The chronological process can be traced back to at least 1 929, in which a simple form of continuous flow electrostatic inkjet printing is disclosed in U.S. Patent No. 1,94,001, issued to Hansell.

A method of continuous ink jet printing is also disclosed in U.S. Patent No. 3,596,275 which comprises the use of a high frequency electrostatic field to modulate the jet stream for droplet separation. This technology is still used in several manufacturing applications, including Elmjet and Seitex (see also US Patent No. 3373437). Piezoelectric inkjet printers are also a common form of inkjet printing apparatus. A piezoelectric system is disclosed in U.S. Patent No. 3, 594, 098 (1 970), which is incorporated herein by reference to U.S. Patent No. 3,832,212 (1970) to Z. A squeezing mode of crystallization is disclosed in U.S. Patent No. 3,747,120 to Stemme (1 972), which discloses a bending mode of the piezoelectric operation, which is disclosed in U.S. Patent No. 445,960, the disclosure of which is incorporated herein by reference. An electric push-out mode is used to actuate the ink jet stream and a shear mode of the piezoelectric transducer element disclosed in U.S. Patent No. 4,558, 590, to F. Recently, thermal spray printing has become an extremely popular inkjet printing technology. Such ink jet printing techniques include the techniques disclosed in British Patent No. GB 2 〇 7l 62 (1 979) and U.S. Patent No. 449072 8 . These two prior art documents disclose an inkjet printing technique that relies on the actuation of a thermoelectric actuator that causes a bubble to be generated in a confined space, such as a nozzle, thereby causing ink to pass from a connection to The hole in the confined space is ejected onto an associated printing medium. Columns using thermoelectric actuators -6 - 200836932 (3) Printing units are manufactured by Canon and Hewlett Packard. It can be seen from the above that many printing techniques are available. Preferably, a printing technique should have several desired aspects. These include low-cost construction and operation, high-speed operation, safe and continuous operation for a long time. Each technology has its own advantages and disadvantages in terms of cost, speed, quality, reliability, power usage, ease of construction, durability and consumability.

When building any inkjet printing system, there are a number of important factors that must be mutually compromised, especially when manufacturing large format printheads, such as page width printheads. First, inkjet printheads are typically built using microelectromechanical systems (MEMS) technology. Therefore, they basically rely on standard integrated circuit structures/manufacturing techniques for depositing planar layers on a germanium wafer and etching portions of the planar layers. Some of the techniques are well known in the art of germanium circuit fabrication. For example, techniques associated with the fabrication of CMOS circuits are more likely to be used more readily than techniques for fabricating exotic circuits including ferroelectric materials, gallium arsenide, and the like. Therefore, it is preferable to use a semiconductor fabrication technique that has been reliably verified in any Μ E M S structure, and does not require any "fancy" processes and materials. Of course, a certain degree of compromise must be taken, because if the benefits of using exotic materials far outweigh its disadvantages, then the use of this material becomes necessary. However, if more general materials are used to achieve the same or similar characteristics, the problem of exotic materials can be avoided. A desirable feature of an inkjet printhead is a versatile inkjet -7-200836932 (4) surface ("front" or "nozzle surface"), preferably with a hydrophilic nozzle chamber and Ink pipe. The hydrophilic nozzle chamber and the ink supply conduit provide a capillary action' which is therefore optimal for droplet alignment after droplet ejection and for resupply of droplets. A hydrophobic front surface minimizes the tendency of the droplets to overflow the entire front surface of the printhead. In the case of a hydrophobic front surface, the liquid ink jet ink does not spill out of the nozzle openings laterally. Moreover, any ink spilling from the nozzle openings will not diffuse over the front surface and will mix on the front side, which in turn will form separate spherical microdroplets which can be handled by appropriate maintenance operations. Easy to manage. However, while hydrophobic front and hydrophilic ink chambers are desirable, there is a large gap in the manufacture of such print heads using MEMS technology.

problem. The final stage of MEMS printhead fabrication is typically the ashing of the photoresist using oxygen plasma. However, the organic hydrophobic material deposited on the front side is typically removed by ashing to leave a hydrophilic surface. Furthermore, a problem with post-ashing vapor deposition of hydrophobic materials is that the hydrophobic material will be deposited in the nozzle chambers and will be deposited on the front side of the printhead. The nozzle chamber walls become hydrophobic, which is extremely disadvantageous in creating a positive ink pressure towards the nozzle chambers. This is a problem that creates a huge demand for print head manufacturing. Accordingly, it is desirable to provide a print head manufacturing method in which the manufactured print head has improved surface characteristics and which does not have the surface characteristics of the nozzle chamber. It is also desirable to provide a method of manufacturing a print head having a hydrophobic front face that is hydrophobic to the printhead. 200836932 (5) [Summary content]

In a first aspect of the invention, the invention provides a method of making a printhead having a hydrophobic inkjet surface. The method comprises the steps of: (a) providing a partially prepared printhead comprising a plurality of printheads a nozzle chamber and a relatively hydrophilic nozzle surface, the nozzle surface defining the inkjet surface to a lesser extent; (b) depositing a relatively hydrophobic polymeric material on the nozzle surface, the polymeric material being resistant to ashing And (c) defining a plurality of nozzle openings on the nozzle surface to provide a relatively hydrophobic inkjet surface printhead, wherein steps (b) and (c) can be performed in any order. Preferably, step (c) is performed prior to step (b), and the method includes the further step of defining a corresponding plurality of aligned nozzle openings on the deposited polymeric material. Selecting the upper layer, the respective plurality of aligned nozzle openings are formed by photopatterning the polymer. The upper layer is selected, the step (c) is carried out after the step (b), and the polymer material is used as a mask for etching the surface of the nozzle. Optionally, the polymeric material is used by the light pattern to define a plurality of nozzle opening regions prior to etching the nozzle surface. Selecting the upper layer, the step (c) is performed after the step (b), and the step (c) comprises the steps of: depositing a mask on the polymeric substance; patterning the mask to the polymer Multiple nozzle opening areas are removed from the mask; -9- 200836932 (6) The polymer material of the removed mask and the underlying nozzle surface are etched to define a plurality of nozzle openings; and the mask is removed. The upper layer is selected, the mask is a photoresist, and the photoresist is removed by ashing. Selecting the upper ground, an identical gas chemistry is used to uranize the polymer and the surface of the nozzle. Λ Selecting the upper layer, the gas chemistry comprises oxygen and a fluorine-containing composite. In the partially prepared print head, the top of each nozzle chamber is a sacrificial photoresist holder. Supported, the method further includes the step of removing the photoresist holder by ashing. The upper chamber is selected such that the top of each nozzle chamber is at least partially defined by the nozzle surface.

Optionally, the nozzle surface is spaced from a substrate such that the sidewall of each nozzle chamber extends between the nozzle surface and the substrate. Selecting the upper floor, the top and side walls of each nozzle chamber are made of ceramic material that can be deposited by CVD. The upper and the side walls are selected from a group selected from the group consisting of cerium oxide, cerium nitride and cerium oxynitride. Optionally, the hydrophobic polymeric material forms a passive surface oxide in an oxygen plasma. Upon selection, the hydrophobic polymeric material recovers its hydrophobicity upon receipt of the oxygen plasma. -10- 200836932 (7) In the case of the upper layer, the hydrophobic polymeric substance is selected from the group consisting of polymerized siloxanes and fluorinated polyolefins. Selectively, the polymeric material was selected from the group consisting of polydimethyl siloxane (PDMS) and perfluoroethylene (PEPE). At the top, at least a portion of the polymeric material is UV cured after deposition. In a further aspect of the invention, the invention provides a print head made by the method of the invention or a print made by the method of the invention in a second aspect of the invention, the invention provides a A printhead having an inkjet surface, wherein at least a portion of the inkjet surface is coated with a hydrophobic polymeric material selected from the group consisting of polymerized decane and fluorinated polyolefin.

The upper layer is selected to be a photoresist and can be removed by ashing. Optionally, the hydrophobic polymeric material forms a passive surface oxide in an oxygen plasma. Upon selection, the hydrophobic polymeric material recovers its hydrophobicity upon receipt of the oxygen plasma. Selectively, the polymeric material was selected from the group consisting of polydimethyl siloxane (PDMS) and perfluoroethylene (PEPE). In a further aspect of the invention, the invention provides a printhead comprising a plurality of nozzle assemblies formed on a substrate, each nozzle assembly comprising: a nozzle chamber, a nozzle opening defined in the nozzle chamber A chamber top and an actuator are used to eject ink through the nozzle opening. -11 200836932 (8) The upper surface is selected, and a nozzle surface on which a hydrophobic polymer is applied at least partially defines the ink jet surface. Selecting the upper floor, each chamber top defining at least a portion of the nozzle surface of the print head, each chamber top having a hydrophobic outer surface relative to the inner surface of each nozzle chamber due to the nature of the hydrophobic coating . Optionally, at least a portion of the inkjet surface has a contact angle greater than 90^ and the inner surfaces of the nozzle chambers have a φ contact angle of less than 90 degrees. Selecting the upper floor, each nozzle chamber contains a chamber top and side walls made of ceramic material. Selecting the upper layer, the ceramic material is selected from the group consisting of cerium oxide, cerium nitride and cerium oxynitride. Optionally, the top of the chamber is spaced from a substrate such that the sidewall of each nozzle chamber extends between the nozzle surface and the substrate. The upper ink jet surface is selected to be hydrophobic relative to the ink supply tube in the print head. ^ Selecting the ground, the actuator is a heater element that is constructed to form a bubble in the chamber to force an ink droplet through the nozzle opening. The upper element is selected and the heater element is suspended within the nozzle chamber. Selecting the upper body, the actuator is a thermal bending actuator comprising: a first active component for connecting to the drive circuit; and a second passive component mechanically cooperating with the first component such that When current is passed through the first component, the first component expands relative to the second element-12-200836932 (9), causing bending of the actuator. The upper bend is selected to define at least a portion of the roof of each nozzle chamber whereby actuation of the actuator moves the actuator toward the chamber floor of the nozzle chamber. The upper nozzle is selected to be defined on the actuator or on a stationary portion of the roof.

Optionally, the hydrophobic polymeric material defines a mechanical seal between the actuator and a portion of a stationary portion of the roof to minimize ink leakage during actuation. Selecting the upper layer, the hydrophobic polymeric substance has a Young's modulus of less than 100 MPa. In a third aspect of the invention, the invention provides a nozzle assembly for an ink jet print head, the nozzle assembly comprising: a nozzle chamber having a chamber top, the chamber top having a movable portion Relative to a stationary portion of the movement and a nozzle opening defined on the top of the chamber such that movement of the movable portion relative to the stationary portion may cause ink to be ejected through the nozzle opening; an actuator for the active a portion that moves relative to the stationary portion; and a mechanical seal that joins the movable portion to the stationary portion, wherein the mechanical seal comprises a polymeric material comprising a polymerized siloxane and Selected from the group of fluorinated polyolefins. The upper nozzle is selected and the nozzle opening is defined on the portion of the activity. -13- 200836932 (10) Selecting the upper ground, the nozzle opening is defined on the stationary part. Selecting the upper body, the actuator is a thermal bending actuator comprising: a first active component for connecting to the drive circuit; and a second passive component mechanically cooperating with the first component such that When current is passed through the first component, the first component expands relative to the second component, causing bending of the actuator. 'Selecting the ground, the first and second components are cantilever beams. Φ Selecting the upper portion, the actuator defines at least a portion of the active portion of the chamber top whereby actuation of the actuator moves the actuator toward the chamber floor of the nozzle chamber. Selecting the upper layer, the hydrophobic polymeric substance has a Young's modulus of less than 100 MPa. Selectively, the polymeric material was selected from the group consisting of polydimethyl siloxane (PDMS) and perfluoroethylene (PEPE). Selecting the upper layer, the polymer is hydrophobic and resistant to ashing. 'Selecting the upper layer, the polymer is restored to its hydrophobicity after receiving oxygen plasma. Optionally, the polymeric material is applied to the entire surface of the chamber or the like such that the ink jet surface of the printhead is hydrophobic. Selecting the upper layer, each chamber top defining at least a portion of the nozzle surface of the print head, each chamber top having a hydrophobic outer surface relative to the inner surface of each nozzle chamber due to the nature of the polymer coating . Optionally, the polymeric coating has a contact angle of greater than 90 degrees -14 - 200836932 (11) degrees and the inner surfaces of the nozzle chambers have a contact angle of less than 90 degrees. The upper polymer layer is selected to have a contact angle of greater than 110 degrees. The upper surface of the nozzle chamber is selected to have a contact angle of less than 70 degrees. Optionally, the nozzle chamber includes a sidewall extending between the top of the chamber and a substrate such that the chamber top is spaced from the substrate. The upper roof and the side walls are formed of a ceramic material deposited by CVD. Selecting the upper layer, the ceramic material is selected from the group consisting of cerium oxide, cerium nitride and cerium oxynitride. [Embodiment]

The invention can be used with any type of print head. Many ink jet print heads have been described in this application, and it is not necessary to describe all of these print heads to understand the present invention. However, the present invention will now be described in conjunction with a thermal bubble forming ink jet print head and a mechanical thermal bending actuated ink jet print head. The advantages of the invention will become apparent from the discussion that follows. Thermal Bubble Forming Inkjet Printhead Referring to Figure 1, there is shown a portion of a printhead that includes a plurality of nozzle assemblies. Figures 2 and 3 show one of these nozzle assemblies in a side cross-sectional view and a cutaway perspective view.

Each nozzle assembly contains a nozzle chamber 24 that uses MEMS •15- 200836932 (12)

Manufacturing techniques are formed on a wafer substrate 2. The nozzle chamber 24 is defined by a chamber top 21 and a side wall 22 extending between the chamber roof 21 and the substrate 2. As shown in Figure 1, each chamber top is defined by a portion of the nozzle surface 56 that extends across the ink jet surface of the print head. The nozzle surface 56 and sidewalls 22 are formed of the same material deposited by PECVD on a sacrificial support of the photoresist during MEMS fabrication. Typically, the nozzle surface 56 and the side wall 22 are made of a ceramic material such as ruthenium dioxide or tantalum nitride. These hard materials are excellently specific to the robustness of the print head, and their inherent hydrophilic nature is advantageous for supplying ink to the nozzle chamber 1 24 by capillary action. However, the inner (inkjet) surface of the nozzle surface 56 is also hydrophilic, which can cause any spilled ink on the surface to spread. Returning to the details of the nozzle chamber 24, a nozzle opening 26 is defined on the top of each of the nozzle chambers 24. Each nozzle opening 26 is generally elliptical and has an associated nozzle edge 25. The nozzle edge 25 assists in the direction of the drop during printing as well as reducing some of the ink spilling from the nozzle opening 26. The actuator for ejecting ink from the nozzle chamber 24 is a heater element 29 positioned below the nozzle opening 26 and overhanging a recess 8. Current is supplied to the heater element 29 through the electrode 9 of the drive circuit connected to the underlying CMOS layer 5 of the substrate 2. As current passes through the heater element 29, it rapidly superheats the surrounding ink to form a bubble that forces the ink through the nozzle opening. By suspending the heater element 29, -16-200836932 (13) when the nozzle chamber 24 is primed, it can be completely submerged in the ink to improve the efficiency of the print head because less heat is dissipated to the bottom. And more of the lost energy is used to create bubbles. As can be clearly seen from Figure 1, the nozzles are provided in rows by an ink supply conduit 27 extending longitudinally of the array of nozzles to provide each nozzle on the oil column. The ink supply conduit 27 delivers ink to the ink inlet passage 15 of the nozzle, which is supplied with ink from the ink conduit 23 in the nozzle chamber 24 by a φ of the nozzle opening 26. The MEMS manufacturing process for the manufacture of such printheads is described in U.S. Patent No. 1 1 / 2 4 6 6 8 8 which was filed on October 1, 2005, the contents of which are hereby incorporated by reference. 4 and 5 show a partially prepared print head comprising 24 including a sacrificial photoresist 10 ("SCA1") and 16 (the SCA1 photoresist 10 is used for heating). The material Φ is used to form the heater element 29. The SCA2 photoresist 16 is a support for the deposition of the sidewall 22 and the roof 21 (which defines a portion of the surface 561). Figures 6 to 8), the MEMS stages are elliptical nozzle edges 25 on the top 2 of the chamber by etching away the 2 micron roofing material 20. The etching layer photoresist (not shown) The defined 'photoresist layer is exposed with a dark tone edge mask of Fig. 6. The elliptical side contains two coaxial edge lips 25a and 25b' in their respective ones. And the deposition of the ink along the inkjet side is applied to the deposition of a nozzle chamber ς SCA 2, The table for the next manufacturing the nozzle lines used to define a dark edge shown package 25 -17-200836932 thermal actuator (14) 29. Referring to Figures 9 through 1, the next stage defines an elliptical spray η on the top of the chamber 2 by etching the remaining material surrounded by the wearer 25. This uranium engraving uses a layer of photoresist (not shown, which is exposed by a dark tone as shown in Figure 9. The elliptical nozzle aperture 26 is tied to the thermal actuator, as shown in Figure 1. The T segments that are fully formed in all MEMS nozzle features are oxygen plasma ashed (Figures 12 and 13) to remove the SAC2 photoresist layers 10 and 16. Figures 14 and 15 show | SAC2 light After the resist layers 10 and 16 are ashed, the germanium wafer 2 has a crucible of 150 μm. Referring to Figures 16 through 18, at the front end MEMS of the wafer, the ink supply conduits 27 are etched using the standard unequal orientation of the back side of the wafer for the side of the ink inlets The etch is defined using a layer of photoresist (not shown) that is exposed by a dark tone mask as shown in FIG. * Channel 27 forms a fluid bond between the back side of the wafer and the oil. Finally, referring to Figures 2 and 3, the wafer is etched by the back side to about 135 microns. Figure 1 shows three adjacent columns of nozzles in a completed printhead body circuit diagram. Each column sprays a respective ink supply conduit 27 that extends along the length of the column and into a plurality of ink inlets 15 in each column. The ink is defined by the edge f-hole 26 to define the top of the chamber reticle 29, and the next step of oxygen is SAC1 $ SAC1 and a thickness (: DRIE is encountered when the ruling is completed. The resistance is thinned by the ink inlet of the ink supply tube. "The cut-off stand: the mouth has a supply port for the supply of -18-200836932 (15) ink to the ink conduit 23 for each column, each of which The nozzle chambers all receive ink from an ink conduit common to the column. As discussed above, prior art MEMS fabrication processes inevitably leave a hydrophilic inkjet surface because the nozzle surface 56 is made of ceramic material. Into, such as cerium oxide, cerium nitride, cerium oxynitride, nitrogen

V aluminum and so on.

Another alternative to the above described treatment after nozzle etch followed by hydrophobic polymer coating is that immediately after the nozzle opening etch (i.e., at the stage represented by Figures 10 and 11), the nozzle surface 5 6 A polymer having a hydrophobicity is deposited thereon. Since the photoresist support layers must be removed in subsequent processing, the polymeric material must be resistant to ashing. Preferably, the polymeric material is required to withstand the removal of oxygen or hydrogen plasma ashing. Applicants have identified a family of polymeric materials that are both hydrophobic and resistant to oxygen or hydrogen ashing. These polymeric materials are typically polymerized siloxanes and fluorinated polyolefins. More specifically, both polydimethylsiloxane (PDMS) and perfluoropolyethylene (PEPE) have shown particular advantages. These materials form a passive surface oxide in the oxygen plasma and then recover their hydrophobicity fairly quickly. Another advantage of these materials is that they have excellent adhesion to ceramics such as cerium oxide and tantalum nitride. Another advantage of these materials is that they are photopatternable, which makes them particularly suitable for use in MEMS processing. For example, PDMS is UV-curable, whereby the PDMS region that is not exposed -19-200836932 (16) can be removed quite easily. Referring to Figure 10, there is shown a nozzle assembly of a partially manufactured printhead after edge etching and nozzle etching as described earlier. However, at this stage, a thin layer of hydrophobic polymer material 100 (ca 1 micron) is applied to the nozzle surface 56 instead of the ashing treatment of SAC1 and SAC2 shown in Figs. 12 and 13, as shown in the figure. 19 and 20 are shown. After deposition, this layer of polymer is photopatterned to remove material deposited by φ in the nozzle opening 26. The photo patterning can include exposing the polymer layer 100 to UV light, except in areas within the nozzle opening 26. Thus, as shown in Figures 21 and 22, the printhead now has a hydrophobic nozzle surface, and subsequent MEMS processing steps can be performed similar to the steps described with reference to Figures 1 2-1. It is important that the hydrophobic polymer 100 is not removed by the oxygen ashing step used to remove the photoresist holders 10 and 16. Φ coating the hydrophobic polymer prior to nozzle etching and treating the polymer as an etch mask as an alternative treatment, the hydrophobic polymer layer 100 followed by the stages represented by Figures 7 and 8 Deposited. Thus, after the edge 25 is defined by edge etching, the hydrophobic polymer is applied to the nozzle surface before the nozzle opening 26 is defined by nozzle etching. Referring to Figures 23 and 24, there is shown a nozzle assembly after deposition of the hydrophobic polymer. The polymer 1 〇〇 is then photopatterned for removal -20- 200836932 (17) material falling within the edge 25 of the nozzle opening region, as shown in Figures 25 and 26. Thus, the hydrophobic polymer 100 can now function as an etch mask for etching the nozzle opening 26. The nozzle opening 26 is defined by etching through the roof structure 21, which is typically implemented using a chemical comprising oxygen and a fluorinated hydrocarbon such as CF4 or C2F8. Hydrophobic compounds, such as PDMS, and PFPE, are typically etched under the same conditions. However, since a substance such as φ is tantalum nitride is etched faster, the chamber top 21 can be selectively etched using PDMS or PFPE as an etching mask. In contrast, at a gas ratio of (CF4: 02) of 3:1, tantalum nitride is etched at about 240 microns per hour, while PDMS is etched at about 20 microns per hour. Therefore, the PDMS mask can be used to define the etch selectivity when defining the nozzle opening 26. When the chamber top 21 is etched to define the nozzle opening, the nozzle assembly 24 is as shown in Figures 21 and 22. Thus, subsequent MEMS processing φ steps can be performed similar to the steps described with reference to Figures 12-18. It is important that the hydrophobic polymer 100 is not removed by removing the photoresist holder ^ 1 〇 and the oxygen ashing step of 16. Applying a hydrophobic polymer prior to etching the nozzle m with an additional photoresist mask. Figures 25 and 26 show how the hydrophobic polymer 100 is used as an etch mask for a nozzle opening etch. Typically, the difference in etch rate between polymer 1 〇〇 and the chamber top 21 as described above provides sufficient etch selectivity. -21 - 200836932 (18) However, in the case where there is insufficient engraving selectivity, a layer of photoresist (not shown) may be deposited on the hydrophobic polymer 100 as shown in Fig. 24, which may allow Traditional downstream MEMS processing. By patterning the photoresist top layer, the hydrophobic polymer 1 and the chamber top 21 can be etched from the same gas chemistry, wherein the photoresist top layer is used as a standard etch. Cover. A CF4/02 gas chemistry is first etched through the hydrophobic polymer 1 〇〇 and then through the chamber top 21 .

Subsequent oxygen ashing can be used to remove only the top layer of the photoresist (to obtain the nozzle assembly as shown in Figures 1 and 11), or extended oxygen ashing can be used to remove the top layer of the photoresist. And sacrificing the photoresist layers 10 and 16 (or obtaining the nozzle assembly as shown in Figures 12 and 13). In addition to the three examples mentioned above, those skilled in the art can imagine other alternative MEMS processing step sequences. However, it will be appreciated that in finding a hydrophobic polymer that can withstand oxygen and hydrogen ashing, the inventors have provided a viable way to provide a hydrophobic nozzle surface to an ink jet column. In the head process. Hot Bending Actuator Printhead The manner in which the nozzle surface of a printhead can be rendered hydrophobic has been discussed above, and it should be understood that any type of printhead can be hydrophobicized in the same manner. However, the present invention achieves the particular advantages associated with the printheads of the hot bending actuator nozzle assembly previously described by the Applicant. Therefore, the article will explain how the invention can be used in these print heads. -22- 200836932 (19) In a thermal bending actuated print head, a nozzle assembly can include a nozzle chamber having a chamber top portion that is movable relative to a chamber bottom plate portion of the chamber. The movable roof portion is typically actuated by a two-layer hot bending actuator for movement toward the floor portion of the chamber. The actuator can be disposed outside of the nozzle chamber or it can define a movable portion of the roof structure.

An active roof is advantageous because it reduces the droplet ejection energy by allowing only one side of the active structure to act on the viscous ink. However, one problem associated with the roof structure of such activities is that it is necessary to seal the ink inside the nozzle chamber during actuation. Typically, the nozzle chamber requires a fluid seal that utilizes the surface tension of the ink to form a seal. However, such seals are imperfect and it is desirable to form a mechanical seal that avoids relying on surface tension as a means of sealing the ink. This mechanical seal must be flexible enough to withstand the bending motion of the roof. A typical nozzle assembly 400 having a movable roof structure is disclosed in U.S. Patent Application Serial No. 1 1/67,976, which issued on Dec. 4, 2006, the content of which is hereby incorporated by reference. This article is also shown in Figures 27 to 3 of the present case. The nozzle assembly 400 includes a spray 401 formed on a passive CMOS layer 402 of a substrate 403. The nozzle chamber is defined by a chamber top 404 and a sidewall extending from the top of the chamber to the passive CMOS layer 402. The ink is supplied to the nozzle chamber 401 by an ink inlet 406 in fluid communication with an ink supply tube 407 that receives ink from the back side of the crucible substrate. The ink is ejected from the nozzle chamber 401 via a nozzle opening 408 defining the -23-200836932 (20) on the chamber top 404. The nozzle opening 408 is offset from the ink inlet 406. As shown in Figure 28, the roof 404 has a movable portion 409 which defines a substantial portion of the total area of the roof 404. Typically, portion 409 of the activity defines at least 50% of the total area of the roof 404. In the embodiment illustrated in Figures 27 through 30, nozzle opening 408 and nozzle edge 415 are 'defined within the movable portion 409 such that the nozzle opening and nozzle edge φ move with the active portion. The nozzle assembly 400 is characterized in that the movable portion 409 is defined by a thermal bending actuator 410 having a flat upper main moving beam 411 and a flat lower passive beam 412. Thus, the actuator 410 typically defines at least 50% of the total area of the chamber roof 404. Accordingly, the upper active beam 41 1 typically defines at least 50% of the total area of the roof 404. As shown in Figures 27 and 28, at least a portion of the upper active beam 4 1 1 is spaced apart from the lower passive beam 4 1 2 to achieve maximum thermal isolation between the two beams. Φ In detail, a layer of titanium is used as the bridging layer 413 between the upper active beam 411 made of TiN and the lower passive beam 412 made of Si〇2. The bridge layer ^ 4 1 3 has a gap 4 1 4 formed between the active and passive beams in the actuator 4 1 0. This gap 4 1 4 improves the overall effect of the actuator 4 10 by minimizing heat transfer from the upper active beam 4 1 1 to the lower passive beam 4 1 2, however, it will be understood The upper active beam 4 1 1 can be directly welded or bonded to the lower passive beam 4 to improve the rigidity of the structure. Such design modifications are within the foreseeable scope of those skilled in the art. -24- 200836932 (21) The upper active beam 411 is 4 1 6 (positive and ground) through the titanium bridging layer. The contacts 4 〖6 are in position with the driver circuit. When it is necessary to eject an ink liquid from the nozzle chamber 401, the upper active beam 4 1 1 between the two contacts 4 16 . The speed is heated by the current and relative to the lower passive beam 4 1 2 'the actuator 410 (which defines the activity of the top chamber 404 to bend downwardly toward the substrate 403. Due to movement between the movable stationary portion Portion 409, which is too small in gap 460 between portions 461, is actuated to move the gap toward the substrate 403 to seal the gap. The movement of the actuator 410 causes the ink to rapidly rise from the nozzle opening 408 due to the pressure of the portion. At the time of spraying, the active portion 409 of the chamber top 04 will recover, and this will draw ink from the inlet 406 into the nozzle φ for the next ink jet. ' Turning to Figure 12, it can be clearly seen that ^ An array of nozzle assemblies for defining a row of heads. A row of head assemblies includes a substrate, an array of nozzle assemblies (typically arranged in rows to drive the nozzle assembly. Multiple prints) The heads are connected or joined together to form a one-page wide inkjet print. The U.S. Patent Application No. issued on May 27, 2004 and the U.S. When the drops in the CMOS layer, the current flows through the active 4 1 1 is swollen, so that part 409) of the portion 409 is caused by this, so that when the activity is active, the nozzle chamber 401 can be relied on by the surface. When the current stops to the position 401 of its stationary position, The nozzle assembly can be electroformed onto the substrate by the complex or print head assembly, and the circuits can be placed against each other in the head, as in the applicant's patent application No. 1 0/854, 49 1 I patent application The contents of the two applications, which are hereby incorporated by reference herein, are incorporated herein by reference. Another nozzle assembly 500, shown in Figures 31-33, is similar to nozzle assembly 400 in that it defines a movable portion of the chamber top 504 of the nozzle chamber 501 as a thermal bending actuator 510, wherein the thermal bending The actuator has an upper active beam 511 and a lower passive beam 512.

However, contrary to the nozzle assembly 400, the nozzle opening 508 and the edge 515 are not defined by the active portion of the chamber top 504. Rather, the nozzle opening 508 and the edge 515 are defined on a fixed or stationary portion 561 of the chamber top 504 such that the actuator 5 10 is independent of the droplet during ejection. Self-moving outside the nozzle opening and edge. One benefit of this structure is that it provides smoother control over the direction of flight of the droplet. Again, the small dimension of the gap 560 between the active portion 59 and the stationary portion 561 can be created by utilizing the surface tension of the ink to create a fluid seal during actuation. Nozzle assemblies 400 and 500 and corresponding print heads can be fabricated in the same manner as the MEM S process described above. In all of the examples, the top (active or stationary) of the nozzle assembly is formed by depositing a chamber top material onto a suitable sacrificial photoresist holder. Referring now to Figure 34, it can be seen that the nozzle assembly 400 illustrated in Figure 27 now has an additional hydrophobic polymer layer 110 (coated as detailed above) coated on top of the chamber, including The movable portion 409 and the stationary portion 461 of the top of the chamber. It is important that the hydrophobic polymer layer 101 seals the gap 460 as shown in FIG. Polymer (such as -26- 200836932 (23)

It is preferred that PDMS and PFPE) have extremely low hardness. Typically, these materials have a Young's modulus of less than 10 MPa and are typically 500 MPa. This feature is advantageous because it allows them to form a mechanical seal within the thermally curved actuator nozzle assembly described herein that elastically stretches during actuation without significantly retarding the The movement of the actuator. Indeed, a resilient seal assists the bending actuator in returning to its original resting position as droplet ejection occurs. Moreover, when there is no gap between the movable ceiling portion 409 and the strong ceiling portion 461, the ink is completely sealed within the nozzle chamber 40 1 during actuation and cannot leak out, only from the nozzle opening 408 spouted. Figure 3 shows a nozzle assembly 5 00 having a hydrophobic polymer coating 1 〇 1 . In contrast to nozzle assembly 400, it will be appreciated that by sealing the gap 560 with the polymer 101, a mechanical seal 562 can be formed to provide ink within the nozzle chamber 501. Excellent mechanical seal. It will be apparent to those skilled in the art that many variations and/or modifications can be made in the present inventions in a particular embodiment without departing from the spirit and scope of the invention. Therefore, the embodiments are to be considered in all respects as illustrative and not limiting. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which FIG. 1 is a partial perspective of an array of nozzle assemblies of a thermal ink jet type print head -27-200836932 (24 Figure 2 is a side view of the nozzle assembly unit cell of Figure 1; Figure 3 is a perspective view of the nozzle assembly of Figure 2; Figure 4 shows the portion of the deposition chamber top and sidewall material after being deposited on a sacrificial photoresist layer Figure 5 is a perspective view of the nozzle assembly of Figure 4; Figure 6 is a mask associated with the edge etching of the nozzle of Figure 7; Figure 7 shows the etching of the top layer of the chamber to form the nozzle opening edge; Figure 8 is a perspective view of the nozzle assembly of Figure 7; Figure 9 is a mask associated with the nozzle opening of Figure 10; Figure 1 shows the etching of the chamber top material to form the elliptical nozzle opening Figure 11 is a perspective view of the nozzle assembly of Figure 10; Figure 12 shows oxygen plasma ashing of the first and second sacrificial layers; Figure 13 is a perspective view of the nozzle assembly of Figure 12;

Figure 14 shows the nozzle assembly after ashing, and the opposite of the wafer Figure 15 is a perspective view of the nozzle assembly of Figure 14; Figure 16 shows the mask associated with the back side of Figure 17; 1 7 shows the back side etching of the ink supply pipe entering the wafer; FIG. 18 is a perspective view of the nozzle assembly of FIG. 17; FIG. 19 shows the deposition of a hydrophobic polymer coating after FIG. Figure 20 is a perspective view of the nozzle assembly of Figure 19; -28- 200836932 (25) Figure 21 shows the nozzle assembly of Figure 19 after photo-patterning of the polymer coating; Figure 22 is Figure 21 Figure 23 shows a nozzle assembly of Figure 7 after depositing a hydrophobic polymer coating; Figure 24 is a perspective view of the nozzle assembly of Figure 23; ^ Figure 25 shows light patterning of the polymer coating Figure 23 is a perspective view of the nozzle assembly of Figure 25; Figure 27 is a side cross-sectional view of an ink jet nozzle assembly including a chamber top having a thermal bending actuator Part of the defined activity; Figure 28 is the cut open of the nozzle assembly of Figure 27. Figure 29 is a perspective view of the nozzle assembly of Figure 27; Figure 30 is a cutaway perspective view of the array of nozzle assemblies of Figure 27; Figure 31 is a side cross-sectional view of another ink jet nozzle assembly including a a top view of the movable portion defined by a thermal bending actuator; Fig. 32 is a cutaway perspective view of the nozzle assembly of Fig. 31; Fig. 33 is a perspective view of the nozzle assembly of Fig. 31; Fig. 34 is a perspective view of Fig. The nozzle assembly has a polymer coating on top of the chamber that forms a mechanical seal between a movable chamber top portion and a stationary chamber top portion; and Figure 35 shows the nozzle assembly of Figure 31 having a The polymer coating is on top of the chamber 'which forms a mechanical seal between a movable top portion and a stationary top portion. -29- 200836932 (26) [Explanation of main component symbols] 2 : 矽 substrate 21 : room top 22 : side wall

24: Nozzle chamber 56: Nozzle surface 2 6 : Nozzle opening 25: Nozzle edge 2 9 : Heater element 8 : Pit 9 : Electrode 5 : CMOS layer 2 7 : Ink supply pipe 15 : Ink inlet passage 23 : Ink conduit 10 : Sacrificial photoresist (SAC1 ) 16 : Sacrificial photoresist (SAC2 ) 2 0 : Room top material 25a : Edge lip 2 5 b : Edge lip 26 Nozzle hole 29 : Thermal actuator 1 0 〇: Polymer layer - 30 200836932 (27) 4 00 : Nozzle assembly 401 : Nozzle chamber 4 02 : CMOS layer 403 : tantalum substrate 4 0 4 : chamber top 405 : side wall 4 0 6 : ink inlet

407: ink supply pipe 408: nozzle opening 409: movable portion 4 1 5 : nozzle edge 410: thermal bending actuator 4 1 1 : upper active beam 4 1 2 : lower passive beam 4 1 3 : bridging layer 4 1 4 : Clearance 4 1 6 : Contact 460 : Clearance 5 〇〇: Nozzle assembly 5 1 0 : Thermal bending actuator 5 1 1 : Upper active beam 5 1 2 : Lower passive beam 5 0 1 : Nozzle chamber 504 : Roof 200836932 (28) 5 0 8 : Nozzle opening 515 : Nozzle edge 560 : Clearance 561 : Stationary part 5 09 : Active part 瓠 461 : Static part of the fee ' 1 01 : Hydrophobic polymer coating

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Claims (1)

200836932 (1) X. Patent Application 1 1. A method of manufacturing a print head having a hydrophobic inkjet surface, the method comprising the steps of: (a) providing a partially prepared print head comprising a plurality of nozzle chambers And a relatively hydrophilic nozzle surface, the nozzle surface defining the inkjet surface to a lesser extent; (b) depositing a relatively hydrophobic polymer layer on the nozzle surface φ, the polymer material resisting ashing And (c) defining a plurality of nozzle openings on the nozzle surface to provide a relatively hydrophobic inkjet surface printhead, wherein steps (b) and (c) can be performed in any order. 2. The method of claim 1 wherein step (c) is performed prior to step (b) and the method further comprises defining a plurality of aligned nozzle openings on the deposited polymeric material. A step of 3. The method of claim 2, wherein the respective plurality of aligned nozzle openings are defined by photopatterning the polymer. 4. The method of claim 1, wherein step (c) is performed after step (b) and the polymeric material is used as a mask for etching the nozzle. 5. The method of claim 4, wherein the polymeric material is used by the light pattern to define a plurality of nozzle opening regions prior to etching the nozzle surface. -33 - 200836932 (2) 6 · Patent Application No. 1 The method of the present invention, wherein the step (c) is performed after the step (b), and the step (c) comprises the steps of: depositing a mask on the polymeric substance; patterning the mask to the polymer A plurality of nozzle opening areas are removed from the mask, and the polymer material of the removed mask and the bottom nozzle surface are etched to: define a plurality of nozzle openings; and 0 to remove the mask. 7. The method of claim 6, wherein the mask is a photoresist and the photoresist is removed by ashing. 8. The method of claim 6, wherein an identical gas chemical is used to uranize the polymeric material and the nozzle surface. 9. The method of claim 8, wherein the gas chemistry comprises oxygen and a fluorine-containing composite. The method of claim 1, wherein in the partially embossed print head, the top of each nozzle chamber is supported by a sacrificial photoresist 'bracket, the method There is further included a step of removing the photoresist holder by ashing. The method of claim 1, wherein the top of each nozzle chamber is at least partially defined by the nozzle surface. 12. The method of claim 11, wherein the nozzle surface is spaced from a substrate such that a sidewall of each nozzle chamber extends between the nozzle surface and the substrate. 1 3. The method of claim 1, wherein the chamber top and the side wall of each nozzle chamber -34-200836932 (3) are composed of ceramic materials deposited by CVD. The method of claim 1, wherein the top and side walls are formed of a substance selected from the group consisting of: cerium oxide, cerium nitride, and cerium oxynitride. The method of claim 1, wherein the hydrophobic polymeric material forms a passive surface oxide in an oxygen plasma. The method of claim 15, wherein the hydrophobic polymeric material recovers its hydrophobicity after receiving the oxygen plasma. The method of claim 1, wherein the hydrophobic polymeric material is selected from the group consisting of polymerized decane and fluorinated polyolefin. 1 8 _ The method of claim 17, wherein the polymeric material is selected from the group consisting of polydimethyl siloxane (PDMS) and perfluoroethylene (PEPE). The method of claim 1, wherein at least some portions of the polymeric material are UV hardened after deposition. 2 0. A type of print head that can be made or can be made by the method of claim 1 of the scope of the patent application. -35-