JP2010173327A - Paddle for jetting liquid and liquid jetting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a micromechanical plunger for ink discharge. <P>SOLUTION: A paddle 8 jets out liquid from the interior of a nozzle chamber 2 through an ink jetting nozzle 4 defined in one wall of the nozzle chamber 2. The paddle 8 includes a first part and a second part, wherein the first part is configured to provide an approximately flat plunger surface which is opposed to the ink jetting nozzle 4 upon usage and disposed to be spaced away from the ink jetting nozzle 4, and the second part is formed on the surface of the plunger around the first part and structurally supports the first part. Thus, upon usage, while the plunger is actuated to jet out the ink through the ink jetting nozzle 2, the second part functions as a spacer to prevent the plunger surface from being in contact with the ink jetting nozzle 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the field of micromechanical or microelectromechanical devices such as inkjet printers. In the present specification, the present invention will be described with reference to microelectromechanical inkjet technology. However, the present invention has broader application to other micromechanical or microelectromechanical devices, such as microelectromechanical pumps and microelectromechanical movers.

  Micromechanical and microelectromechanical devices are becoming increasingly popular and typically involve the creation of micron scale devices using semiconductor manufacturing techniques. For a recent overview of micromechanical devices, refer to the paper “The Broad Sweep of Integrated Micro Systems” in Non-Patent Document 1.

One type of commonly used microelectromechanical device is an ink jet printing device in which ink is ejected from an ink ejection nozzle chamber. Many types of inkjet devices are known.
Many different techniques for ink jet printing and related devices have been invented. As an overview of this field, reference is made to the paper “Non-Impact Printing: Introduction and Historical Perspective” of Non-Patent Document 2.

  Recently, the applicant has developed a new type of inkjet printing called microelectromechanical inkjet (MEMJET) technology. In one form of MEMJET technology, ink is ejected from an ink ejection nozzle chamber that utilizes an electromechanical actuator connected to a paddle or plunger. The paddle or plunger moves toward the ejection nozzle of the chamber, and ink drops are ejected from the ejection nozzle chamber.

  The present invention relates to improvements in mechanical bending actuators for use in MEMJET technology and other micromechanical or microelectromechanical devices.

S. Tom Picraux; Paul J. McWhorter, IEEE Spectrum, p24-33, Feb., 1998 R. Dubeck; S. Sherr, Output Hard Copy Devices, p207-220, 1988

  According to a first aspect of the present invention, a thermal actuator for a microelectromechanical device is provided. The actuator is a support substrate, an actuating part, and a first arm attached to the actuating part at a first end thereof and attached to the actuating part at a second end so that it can be heated by conduction during use. And a second arm attached to the support substrate at a first end and attached to the actuating part at a second end, spaced from the first arm. And a second arm that is disposed such that the first and second arms define a gap therebetween. During use, the first arm is arranged to thermally expand when heated by conduction, thereby applying a force to the actuator.

Therefore, the dependence of the operating characteristics of the actuator, such as the operating temperature, on the material of the operating portion can be reduced as compared with the conventional thermal actuator. In prior art thermal actuators, the actuating part is usually partly arranged between the arms of the thermal actuator (three-layer actuator). Furthermore, if the actuator is partially located between the arms, during use, shear stress may be induced in that part of the actuator, thereby reducing the efficiency of the actuator. There is.
The actuator may be arranged in such a way that a heating current can be applied to the first arm through the support substrate.

  The first and second arms are preferably formed from substantially the same material. The actuator deposits and etches the first layer to form a first arm, and deposits and etches the second layer to form a sacrificial layer support structure above the first arm. And stacking and etching the third layer to form a second arm and etching the second layer to form a gap between the first arm and the second arm. It may be manufactured.

The first arm may include two elongated flexible strips interconnected by conduction at the second end.
The second arm may include two elongated flexible strips.
The operating part may include a paddle structure. Therefore, the actuator may be used in the liquid ejection chamber with the paddle structure movable relative to the liquid ejection from the liquid ejection chamber.
The first arm may be formed from titanium nitride, and the second arm may be formed from titanium nitride.

  According to a second aspect of the present invention, a novel form of manufacturing an inkjet printing system is disclosed.

  According to a third aspect of the present invention, a paddle is provided that ejects liquid from within a nozzle chamber through a liquid ejection nozzle defined in one wall of the nozzle chamber. A paddle is formed on the plunger surface at a periphery of the first portion and a first portion configured to provide a generally flat plunger surface opposite the nozzle and spaced from the nozzle during use. And a second portion that provides structural support for the first portion so that, in use, the second portion is a spacer while the plunger is actuated to eject liquid through the nozzle. To prevent the plunger surface from touching the nozzle.

  Positioning the plunger surface spaced from the nozzle is important in reducing the likelihood that a liquid meniscus will contact the plunger surface at the nozzle. Contact can affect the operating characteristics of such devices. A person skilled in the art will accordingly respond to this chamber implementing the present invention in the same ejection volume compared to a paddle having a certain thickness previously thought to be structurally robust. It will be understood that the size of can be reduced.

The second portion may be configured to define a continuous wall structure around the central portion with the central portion of the plunger surface generally aligned with the nozzle in use.
The central part may preferably have the same dimensions as the nozzle.
The first portion may have a circular outer periphery, and the second portion may include an annulus around the outer periphery of the paddle.
The paddle may be arranged substantially in contrast around the liquid ejection nozzle, depositing and etching the first layer to form the first paddle portion, and depositing and etching the second layer. Then, the sacrificial layer support structure may be formed above the first paddle part and the third paddle part may be formed by depositing and etching the third layer.

  According to a fourth aspect of the invention, a mechanical actuator is provided for a micromechanical or microelectromechanical device. Such an actuator is a support substrate, an actuating part, and a first arm attached to the actuating part at a first end and attached to the actuating part at a second end, which can be heated by conduction during use. And a second arm attached to the support substrate at the first end and attached to the actuating portion at the second end, spaced from the first arm. And a second arm, wherein the first and second arms define a gap therebetween, and the at least one rigid member connects the first arm and the second arm to each other. Interconnected between the first end and the second end, and in use, the first arm is arranged to thermally expand, thereby causing the actuator to exert a force on the actuator.

  Applicant has discovered that by providing a rigid member between the first arm and the second arm, both arms can be prevented from warping when the first arm expands. did.

The first arm preferably has a first main body formed between a first end and a second end of the first arm, and at least one connected to the first main body. A first of the at least one rigid member may interconnect the tab with the second arm.
The second arm preferably has at least one second main body formed between the first and second ends of the second arm, and at least one connected to the second main body. A first of the at least one rigid member may interconnect both corresponding tabs of the first and second arms.

The tab body may be connected to the first main body through the first thinned neck.
The corresponding tab body may be connected to the second main body through the second thinned neck.

The first arm is such that the first arm can be heated by conduction, causing the first arm to thermally expand with respect to the second arm during use, thereby causing the actuator to exert a force on the actuator. A conductive layer may be included.
The first and second arms are preferably substantially parallel, and the rigid member may be substantially perpendicular to the first and second arms.
The actuators may be arranged in such a way that current can be supplied to the conductive layer through the support substrate.
The first and second arms are preferably formed from substantially the same material.

  The actuator deposits and etches the first layer to form a first arm, and deposits and etches the second layer to form a sacrificial layer support structure above the first arm. Depositing and etching the third layer to form a second arm, etching the sacrificial layer to form a gap between the first arm and the second arm, and May be manufactured.

The first arm may include two elongated flexible strips interconnected by conduction at the second end. The second arm may also include two elongated flexible strips.
The operating part may include a paddle structure. Therefore, the actuator may be used in the liquid ejection chamber with the paddle structure movable relative to the liquid ejection from the liquid ejection chamber.
The first conductive arm may be formed from titanium nitride and the second arm may be formed from titanium nitride.

  According to a fifth aspect of the present invention, a thermal actuator for a micromechanical or microelectromechanical device is provided. Such an actuator is a support substrate, an actuator extension, and a first arm attached to the substrate at its first end and attached to the extension at a second end, which can be heated by conduction during use. And a second arm attached to the support substrate at a first end and attached to an extension at a second end, spaced from the first arm. Arranged in such a way that, in use, the first arm is thermally expanded, whereby the actuator applies a force to the extension, and the first arm is At least one heat sink element is included at approximately the highest heating point of the first arm, which is where maximum heating of the first arm occurs during use.

  Applicants are able to lower the maximum temperature in the first arm by providing a heat sink element and in that a more uniform temperature profile can be achieved throughout the first arm. It was discovered that the operating characteristics of an actuator that bends by heat can be improved. This can maximize the thermal expansion induced in the first arm.

The heat sink element may be disposed substantially in the center of the first arm.
The heat sink element may be arranged to interconnect the first arm and the second arm.
The heat sink element may include at least one tab body connected to the main body of the first arm.
The tab body may be connected to the main body through the first thinned neck.
The first arm may include a conductive layer by which the first arm can be heated by conduction.

The actuators may be arranged in such a way that current can be supplied to the conductive layer through the support substrate.
The first and second arms are preferably formed from substantially the same material.
The extension may include a paddle structure. Therefore, the actuator may be used in the liquid ejection chamber with the paddle structure movable relative to the liquid ejection from the liquid ejection chamber.
The first conductive arm may be formed from titanium nitride and the second arm may be formed from titanium nitride.

  According to a sixth aspect of the present invention, there is provided a first opening in the one wall for ejecting liquid and a second opening in the wall through which the arm of the actuator extends. A liquid ejection device is provided that includes a nozzle chamber having. The actuator arm is attached to a substrate disposed outside the nozzle chamber and connected to a paddle inside the nozzle chamber, the paddle ejecting liquid through the first opening by the actuator arm. Is operable. The system further includes a first raised rim formed around the second opening. The first raised rim is positioned in such a way that during operation of the actuator arm, a liquid meniscus is formed along the outer surface of the liquid between the first raised rim and the actuator arm. ing.

Thus, liquid may be prevented from spreading outside the nozzle chamber through the second opening.
The actuator may preferably include a flat portion adjacent to the first raised rim and generally parallel to and spaced from the substrate.
The first raised rim may preferably include an edge generally parallel to the flat portion.
The first raised rim may include a raised lip.

The device may further include a second raised rim formed on the arm of the actuator adjacent to the first raised rim formed around the second opening. In this embodiment, the second raised rim may help prevent liquid from spreading outside the nozzle chamber through the second opening.
The first raised rim may be formed from a deposition of a layer that also forms part of the arm of the actuator.
At least one of the first and second raised rims may be formed from titanium nitride.
Adjacent to the first raised rim is preferably formed a pit that helps reduce wicking.

  According to a seventh aspect of the present invention, a liquid ejection device is provided. A liquid ejection device is disposed within the nozzle chamber and, when moved from the first state to the ejection state, ejects liquid from the nozzle chamber through an opening in one wall of the nozzle chamber. A paddle and a liquid supply port arranged in such a manner that it is substantially closed by the paddle when the paddle is in the first state. Such a nozzle chamber includes an internal protrusion on its wall structure that is aligned closely adjacent to the rim of the paddle when the paddle is in the first state. In the erupted state, at least a portion of the paddle rim is spaced from the protrusion, thereby defining a liquid refill defined between the wall structure and that portion of the paddle rim. Form a channel.

The internal protrusion may have a stepped cross section.
The paddle and internal protrusion are preferably formed in one deposition process.
The internal protrusion may be formed using a deposition process having a low aspect ratio compared to a high aspect ratio deposition process that forms the wall structure of the nozzle chamber.
The paddle may be substantially flat.

  The preferred form of the invention will now be described, by way of example only, with reference to the accompanying drawings, in spite of any other form that may fall within the scope of the invention.

1 schematically illustrates the operation of a preferred embodiment. 1 schematically illustrates the operation of a preferred embodiment. 1 schematically illustrates the operation of a preferred embodiment. 1 schematically shows a first thermobending actuator. 1 schematically shows a first thermobending actuator. 1 schematically shows a first thermobending actuator. 2 schematically shows a second thermobending actuator. 2 schematically shows a second thermobending actuator. 3 schematically shows a third thermobending actuator. 3 schematically shows a third thermobending actuator. Fig. 4 schematically shows a further thermobending actuator. 12 shows an exemplary graph of temperature with respect to distance for the apparatus of FIG. Fig. 4 schematically shows a further thermobending actuator. Figure 14 shows an exemplary graph of temperature with respect to distance for the device of Figure 13; Fig. 4 schematically shows a further thermobending actuator. FIG. 3 shows a perspective view from the side of the CMOS layer of the preferred embodiment. A 1 micron mask is shown. The top view of a part of CMOS layer is shown. FIG. 3 shows a perspective view from the side of a preferred embodiment having a sacrificial polyimide layer. A top view of a sacrificial polyimide mask is shown. FIG. 3 shows a partial cross-sectional side view of a preferred embodiment having a sacrificial polyimide layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a first level titanium nitride layer. FIG. 3 shows a top view of a first level titanium nitride mask. FIG. 3 shows a partial cross-sectional side view of a preferred embodiment having a first level titanium nitride layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a second level sacrificial polyimide layer. FIG. 6 shows a top view of a second level sacrificial polyimide mask. FIG. 4 shows a partial cross-sectional side view of a preferred embodiment having a second level sacrificial polyimide layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a second level titanium nitride layer. FIG. 3 shows a plan view of a second level titanium nitride mask. FIG. 3 shows a partial cross-sectional side view of a preferred embodiment having a second level titanium nitride layer. FIG. 6 shows a perspective view from the side of a preferred embodiment having a third level sacrificial polyimide layer. FIG. 6 shows a top view of a third level sacrificial polyimide mask. FIG. 6 shows a partial cross-sectional side view of a preferred embodiment having a third level sacrificial polyimide layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a conformal PECVD SiNH layer. FIG. 6 shows a plan view of a conformal PECVD SiNH mask. FIG. 4 shows a partial cross-sectional side view of a preferred embodiment having a conformal PECVD SiNH layer. FIG. 5 shows a perspective view from the side of a preferred embodiment having a conformal PECVD SiNH nozzle tip etch layer. FIG. 6 shows a plan view of a conformal PECVD SiNH nozzle tip etching mask. FIG. 6 shows a partial cross-sectional side view of a preferred embodiment having a conformal PECVD SiNH nozzle tip etch layer. FIG. 2 shows a perspective view from the side of a preferred embodiment having a conformal PECVD SiNH nozzle roof etch layer. FIG. 6 shows a top view of a conformal PECVD SiNH nozzle roof etching mask. FIG. 6 shows a partial cross-sectional side view of a preferred embodiment having a conformal PECVD SiNH nozzle roof etch layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a sacrificial protective polyimide layer. The top view of a sacrificial protective polyimide mask is shown. FIG. 6 shows a partial cross-sectional side view of a preferred embodiment having a sacrificial protective polyimide layer. FIG. 3 shows a perspective view from the side of a preferred embodiment having a back etch layer. The top view of a back etching mask is shown. FIG. 3 shows a side view of a partial cross section of a preferred embodiment having a back etch layer. FIG. 4 shows a perspective view from the side of a preferred embodiment having a stripping sacrificial material layer. FIG. 6 shows a plan view of a stripping sacrificial material mask. FIG. 3 shows a partial cross-sectional side view of a preferred embodiment having a stripping sacrificial material layer. FIG. 2 shows a perspective view from the side of a preferred embodiment with packaging, bonding, priming, and testing. FIG. 2 shows a top view of a packaging, bonding, priming, and test mask. FIG. 4 shows a partial cross-sectional side view of a preferred embodiment with packaging, bonding, priming, and testing. FIG. 3 shows a perspective cross-sectional view from the side of a preferred embodiment ejecting drops. FIG. 2 shows a perspective view from the side of a preferred embodiment when operating. FIG. 3 shows a perspective cross-sectional view from the side of a preferred embodiment ejecting drops. FIG. 4 shows a partial cross-sectional side view of a preferred embodiment when returning. 1 shows a plan view of a preferred embodiment. It is the expansion perspective view seen from the side which shows the arm and nozzle chamber of an actuator. It is the expansion perspective view seen from the side which shows the rim | limb and nozzle chamber of the paddle of an actuator. It is the expansion perspective view seen from the side which shows the heater element of an actuator. FIG. 2 shows a plan view of an array of nozzles formed on a wafer. FIG. 2 shows a perspective cross-sectional view from the side of an array of nozzles formed on a wafer. FIG. 3 shows an enlarged perspective cross-sectional view from the side of an array of nozzles formed on a wafer.

  In a preferred embodiment, a compact type of liquid ejection device is provided that ejects ink from a nozzle chamber utilizing an actuator that bends by heat.

  First, the operating principle of the preferred embodiment will be described with reference to FIGS. As shown in FIG. 1, an ink ejection device 1 is provided. The ink ejection device 1 includes a nozzle chamber 2 that is normally filled with ink and is adapted to form a meniscus 3 around an ink ejection nozzle 4 having a raised rim. The ink in the nozzle chamber 2 is replenished by the ink supply channel 5.

  Ink is ejected from the nozzle chamber 2 by a thermal actuator 7 which is securely interconnected to the nozzle paddle 8. The thermal actuator 7 includes two arms 10 and 11, and the lower arm 11 is interconnected to a current source so as to conduct conduction heating of the lower arm 11. When it is desired to eject drops from the nozzle chamber 2, the lower arm 11 is heated so that this arm 11 expands rapidly with respect to the upper arm 10. This rapid expansion in turn causes the paddle 8 to move rapidly upward in the nozzle chamber 2. FIG. 2 shows this initial movement. The arm 8 moves upward so that the pressure in the nozzle chamber 2 is essentially increased. This pressure increase in turn causes the ink to flow out of the nozzle 4 and the meniscus 3 to swell. Next, the current to the heater 11 is turned off so that the paddle 8 starts to return to its original position as shown in FIG. As a result, the pressure in the nozzle chamber 2 is essentially reduced. Since the ink outside the rim 4 of the nozzle has a momentum forward, as a result, the meniscus is constricted and separated, and the meniscus 3 and the bubbles 13 are formed as shown in FIG. The bubble 13 continues to advance forward onto the ink print medium.

  Significantly, the nozzle chamber includes a longitudinal edge 15 which, as shown in FIG. 2, greatly increases the channel space 16 as the paddle 8 moves up. By increasing the channel space 16 in this manner, the ink is drawn through the channel 16 due to the surface tension effect of the ink meniscus 3, and a substantial amount of ink can rapidly flow into the nozzle chamber 2. The nozzle chamber profile allows the nozzle chamber to be rapidly refilled and the device eventually returns to the rest position as previously shown in FIG.

  The device 1 also includes a number of other important features. These include a circular rim 18 as shown in FIG. The circular rim 18 is formed around the outer periphery of the paddle 8 and substantially increases the distance between the meniscus 3 shown in FIG. 3 and the paddle surface 8 while providing structural support for the paddle 8. Yes. By maximizing this distance, it is less likely that the meniscus 3 will contact the paddle surface 8 and thereby affect the operating characteristics. In addition, as part of the manufacturing process, an ink spill prevention lip 19 is provided to reduce the likelihood that ink will wick along the surface, for example 20, and thereby affect the operating characteristics of the device 1. .

  The operating principle of the thermal actuator 7 will be described first with reference to FIGS. First, referring to FIG. 4, an actuator that is attached to a substrate 22 and bends by heat is shown. The actuator that bends due to heat includes an arm 23 of the actuator, with actuating arms 24, 25 on either side thereof. The two arms 24, 25 are preferably made of the same material and are in thermal balance with each other. Furthermore, it is assumed that the pressure P acts on the surface of the arm 23 of the actuator. If an increase in pressure is desired, the lower arm 25 is heated to reduce the tensile stress between the upper arm 24 and the lower arm 25 as shown in FIG. As a result, a resultant force acting on the actuator arm 23 is output, and as a result, the actuator arm 23 moves upward as a whole.

  Unfortunately, in practice it has been found that if the arms 24, 25 are too long, there is a risk of heating the arm 25 into a warped state as shown in FIG. This warped state reduces the operational effectiveness of the arm 23 of the actuator. The possibility of warping as shown in FIG. 6 can be essentially reduced by utilizing smaller, thermally bent arms 24,25. The apparatus modified in this way is shown in FIG. It has been found that heating the lower thermal arm 25 as shown in FIG. 8 causes the actuator arm 23 to bend upward and the system is essentially less likely to enter the warped state of FIG.

In the apparatus of FIG. 8, the portion 26 of the actuator arm 23 between the actuating parts 24 and 25 is in a shear stress state, which may result in a loss of operational efficiency in this embodiment. Absent. Further, heat may be conducted rapidly from arm 25 to arm 24 as a result of the presence of material 26.
Furthermore, the thermal arm 25 must be operated at a temperature suitable for operating the arm 23. The operating characteristics are therefore limited by the characteristics of the portion 26, such as the melting point.

  FIG. 9 shows another type of actuator that is bent by heat. Such an actuator includes two arms 24 and 25 and an arm 23 of the actuator, and a space or gap 28 is provided between the arms. When one of the arms is heated, the arm 25 bends upward as before as shown in FIG. The apparatus of FIG. 10 has the advantage that the operating characteristics of the arms 24, 25, such as temperature, may not necessarily be limited by the material utilized in the arm 23. Furthermore, the apparatus of FIG. 10 does not induce shear forces within the arm 23 and is less likely to delaminate during operation. These principles are utilized in the heat-bending actuator of the apparatus of FIGS. 1-3 to provide a more energy efficient mode of operation.

  In addition, a number of further efforts are made to provide a more efficient type of thermal actuator. Thermal actuators rely on conductive heating, and the device utilized in the preferred embodiment can be simplified to a material 30 as shown in FIG. The material 30 is interconnected to the substrate at the first end 31 and to the load at the second end 32. The arm 30 is heated by conduction and expands to exert a force on the load 32. When heated by conduction, the temperature profile is approximately as shown in FIG. The two ends 31, 32 serve as “heat sinks” for their conductive heating, so the temperature profile is lower at each end and highest at the center. The operating characteristics of the arm 30 are determined by the melting point 35 in that the arm may not operate if the temperature at the center 36 exceeds the melting point 35. The graph of FIG. 12 shows suboptimal results in that the arm 30 in FIG. 11 is not uniformly heated along its length.

  As shown in FIG. 13, by deforming the arm 30 so as to include the heat sinks 38 and 39 in the central portion of the arm 30, a more preferable thermal profile as shown in FIG. 14 can be achieved. The profile of FIG. 14 is more uniformly heated over the length of the arm 30, thereby making the overall operation more efficient.

  Referring now to FIG. 15, further efficiency and reduced potential for warping can be achieved by providing a series of struts to couple the two actuator actuating arms 24, 25 together. Such an apparatus is shown schematically in FIG. In FIG. 15, a series of struts, for example 40 and 41, are provided to connect the two arms 24 and 25 to prevent warping. Thus, the lower arm 25 is more likely to bend upward when heated, thereby causing the arm 23 of the actuator to also bend upward.

  One form of detailed configuration of the inkjet printing MEMS device will now be described. In some of the drawings, a 1 micron grid as shown in FIG. 17 is utilized as a compliance frame.

  Steps 1 and 2. The starting material is a CMOS wafer 100 that has been suitably processed and deactivated (using silicon nitride) as shown in FIGS.

Step 3. As shown in FIGS. 19 to 21, a 1 micron spin-on photosensitive polyimide 102 is deposited and exposed using ultraviolet light through a mask 104 of FIG. Next, the polyimide 102 is developed.
Since polyimide 102 is sacrificial, a wide range of other materials can be used. In the case of photosensitive polyimide, the steps of deposition, etching, and resist stripping are omitted, so that the processing becomes simple.

  Step 4. As shown in FIGS. 22 to 24, titanium nitride 106 obtained by sputtering a 0.2 micron magnetron is deposited at 300 ° C. and etched using the mask 108 shown in FIG. Thus, a layer including the actuator layer 105 and the paddle 107 is formed.

Step 5. As shown in FIGS. 25 to 27, a 1.5 micron photosensitive polyimide 110 is spun on and exposed using ultraviolet light through a mask 112 in FIG. Next, the polyimide 110 is developed. This thickness ultimately determines the gap 101 between the actuator and the compensating titanium nitride layer and thus affects the amount of bending of the actuator.
Regarding the process 3, by using photosensitive polyimide, the processes of deposition, etching, and resist stripping can be omitted, so that the process becomes simple.

Step 6. 28 to 30, a 0.05 micron conformal PECVD silicon nitride (Si _x N _y H _z ) (not shown due to relative dimensions of various layers) is deposited at 300 ° C. To do. Next, titanium nitride 116 sputtered with a 0.2 micron magnetron is also deposited at 300 ° C. This TiN 116 is etched using the mask 119 of FIG. Next, using this TiN 116 as a mask, the PECVD nitride is etched.

  The good step coverage of TiN 116 is not critical. The top layer of TiN 116 is not electrically connected and is used as a purely mechanical component.

  Step 7. As shown in FIGS. 31 to 33, 6-micron photosensitive polyimide 118 is spun on and exposed using ultraviolet light through the mask 120 of FIG. Next, the polyimide 118 is developed. This thickness determines the height to the nozzle chamber roof. If this height exceeds a certain distance (determined by the droplet splitting characteristics), the actual height is of little importance. However, this height should be limited to reduce stress and increase lithography accuracy. It is easy to provide a 1 micron taper between the top and bottom of the 6 micron polyimide 118.

  Step 8. As shown in FIGS. 34 to 36, 2 micron (thickness exceeding polyimide 118) of PECVD silicon nitride 122 is deposited at 300.degree. This fills the channel formed in the aforementioned PS polyimide layer 118 forming the nozzle chamber. A mask is not used (FIG. 35).

Step 9. As shown in FIGS. 37-39, the PECVD silicon nitride 122 is etched to a nominal depth of 1 micron using the mask 124 of FIG. This etch depth is not critical and may vary up to ± 50%, so this is a simple timed etch.
This etch forms the rim 126 of the nozzle and the rim 128 of the actuator port. Using such a rim, the ink meniscus is fixed at a certain position to prevent the ink from spreading.

Step 10. As shown in FIGS. 40-42, PECVD silicon nitride 122 is etched to a nominal depth of 1 micron and stopped on polyimide 118 using mask 130 of FIG. Variations in the two processes described above can be handled with 100% over-etching, and manufacturing tolerances can be relaxed.
This etching forms the nozzle chamber roof 132.

  Step 11. As shown in FIGS. 43-45, nominally 3 micron polyimide 134 is spun on as a protective layer for back-etching (no mask—FIG. 44).

  Step 12. As shown in FIGS. 46-48, the wafer 100 is thinned to 300 microns (to reduce back etch time) and a 3 micron resist (not shown) on the back side 136 of the wafer 100 is applied to FIG. Exposure is performed through a mask 138. The position is aligned with the metal part 103 on the front side of the wafer 100. This alignment can be performed using an infrared microscope attachment to the wafer aligner.

  The wafer 100 is then etched (from backside 36) using a deep silicon etch “Bosch process” to a depth of 330 microns (allowing 10% overetch). This process is available on plasma etchers from Alcatel, Plasma Therm, and Surface Technology Systems. The chip is also diced by this etch, but the wafer is still held together by various polyimide layers of 11 microns.

  Step 13. As described with reference to FIGS. 49-51, the wafer 100 is turned over and placed in the tray, and all of the sacrificial polyimide layers 102, 110, 118, 134 are etched in an oxygen plasma without a mask. (FIG. 60).

  Step 14. As described with reference to FIGS. 52 to 54, a package is created by drilling a 0.5 mm hold on a standard package and bonding an ink hose (not shown) to the package. The ink hose should include a 0.5 micron absolute filter to prevent nozzle contamination from the ink 121.

FIGS. 55-62 show various views of the preferred embodiment, some of which show an operating embodiment.
Clearly, the large array 200 of printheads 202 can be configured simultaneously, as shown in FIGS. 63-56, which show diagrams of various printhead arrays.

  The ink jet printing technology currently disclosed is suitable for a potentially wide range of printing systems. These printing systems include color and monochrome office printers, short-run digital printers, high-speed digital printers, printers that supplement offset printers, low-cost scan printers, high-speed page width printers, notebook computers with built-in page width printers. , Portable color and monochrome printers, color and monochrome copiers, color and monochrome facsimiles, a combination of printers, facsimiles and copiers, label printers, large format plotters, photocopiers, digital photography “minilabs” Printer, video printer, photo CD printer, PDA portable printer, wallpaper printer, indoor sign printer, outdoor billboard printer, fabric printer, camera printer, and fault tolerance Including an array of commercially available printers.

  Furthermore, the MEMS principle outlined has general applicability in the construction of MEMS devices.

  Those skilled in the art will appreciate that numerous modifications and / or variations may be made to the invention shown in the preferred embodiments without departing from the spirit or scope of the invention as broadly described. Like. The preferred embodiments should therefore be considered in all respects as illustrative and not restrictive.

Claims (19)

A paddle for ejecting liquid from within a nozzle chamber through a liquid ejection nozzle defined in one wall of the nozzle chamber,
A first portion configured to provide a generally flat plunger surface opposite the nozzle and spaced from the nozzle during use;
A second portion formed on the plunger surface in the periphery of the first portion to provide structural support for the first portion, whereby the plunger is actuated to draw liquid during use. A paddle that prevents the plunger surface from touching the nozzle while the second portion acts as a spacer while jetting through the nozzle.   The paddle according to claim 1, wherein the second portion is configured to define a wall structure around the central portion with the central portion of the plunger surface substantially aligned with the nozzle during use. .   The paddle according to claim 2, wherein the central portion has the same dimensions as the nozzle.   4. The paddle according to claim 1, wherein the first portion has a circular outer periphery, and the second portion includes an annular shape around the outer periphery of the paddle. 5.   The paddle according to claim 2, wherein the wall structure is partially cut at the bottom.   The paddle includes depositing and etching a first layer to form the first portion, and depositing and etching a second layer to form a sacrificial layer on a portion of the first portion. Forming a structure, and depositing and etching a third layer to form the second portion, and etching the sacrificial layer to partially cut the lower portion of the second portion. The paddle according to claim 5, wherein the paddle is formed by the step of: A nozzle chamber having a first opening in its one wall for ejecting liquid and a second opening in its wall through which an arm of the actuator extends, said actuator arm Is attached to a substrate disposed outside the nozzle chamber and connected to a paddle inside the nozzle chamber. The paddle passes the liquid through the first opening by an arm of the actuator. A nozzle chamber operable to erupt,
A first raised rim formed around the second opening, wherein the liquid between the first raised rim and the actuator arm during operation of the actuator arm; A first raised rim disposed in such a manner that a liquid meniscus is formed along the outer surface of the liquid ejection device.   8. The liquid ejection device of claim 7, wherein the actuator includes a flat portion adjacent to the first raised rim and substantially parallel to and spaced from the substrate.   The liquid ejection device of claim 8, wherein the first raised rim includes an edge generally parallel to the flat portion.   10. A liquid ejection device according to any one of claims 7 to 9, wherein the first raised rim includes a raised lip.   11. The method of any of claims 7-10, further comprising a second raised rim formed on the arm of the actuator adjacent to the first raised rim formed around the second opening. A liquid ejection device according to claim 1.   12. The liquid ejection device according to any one of claims 7 to 11, wherein the first raised rim is formed from a deposition of a layer that also forms part of the arm of the actuator.   The liquid ejection device according to any one of claims 7 to 12, wherein at least one of the first and second raised rims is formed from titanium nitride.   14. A liquid ejection device according to any one of claims 7 to 13, wherein pits are formed adjacent to the first raised rim to help reduce wicking. A nozzle chamber;
An ejection paddle disposed within the nozzle chamber and ejecting liquid from the nozzle chamber through an opening in one wall of the nozzle chamber when moved from a first state to an ejection state;
A liquid supply port disposed in a manner that is substantially closed by the paddle when the paddle is in the first state;
The nozzle chamber includes an internal protrusion on its wall structure that is aligned closely adjacent to the rim of the paddle when the paddle is in the first state;
In the ejected state, at least a portion of the rim of the paddle is spaced from the protrusion, thereby providing a gap between the wall structure and the portion of the rim of the paddle. A liquid ejection device that forms a liquid refill channel as defined in   The liquid ejection device according to claim 15, wherein the internal protrusion has a stepped cross section.   The liquid ejection device according to claim 15 or 16, wherein the paddle and the internal protrusion are formed in one deposition step.   The internal protrusion is formed using a deposition process having a low aspect ratio compared to a high aspect ratio deposition process that forms the wall structure of the nozzle chamber. Liquid ejecting device according to.   The liquid ejection device according to claim 15, wherein the paddle is substantially flat.

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