JP2006281479A - Method for manufacturing liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid jetting head capable of substantially making delivering characteristics uniform. <P>SOLUTION: The method for manufacturing a liquid jetting head at least comprises an etching process for simultaneously forming feeding spouts corresponding to a plurality of respective flow path substrates on a silicon wafer by etching the silicon wafer integrally formed with a plurality of the flow path substrates for a definite time using a specified protective film as a mask, and a dividing process for dividing the silicon wafer on which the feeding spouts are formed into a plurality of the flow path substrates. In the etching process, the flow path resistances of respective feeding spouts formed on the silicon wafer are made uniform by substantially adjusting at least either one of the width or the length of a narrow channel constituting the divided flow path part of the feeding spouts in accordance with the position within the surface of the silicon wafer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid ejecting head such as an ink jet recording head that ejects ink droplets from nozzles.

  In general, various types of liquid ejecting heads such as ink jet recording heads used in printers, facsimiles, copiers, and the like are known depending on the mechanism for ejecting droplets. For example, the liquid is boiled by a heating element, etc., and droplets are ejected by the bubble pressure generated at that time, or the volume of the pressure generation chamber filled with the droplets is expanded or contracted by the displacement of the piezoelectric element. Some eject liquid droplets from a nozzle. Furthermore, for example, there is a liquid ejection device that discharges liquid droplets from a nozzle by changing the volume of a pressure generation chamber using electrostatic force.

  For example, an electrostatic drive type ink jet recording head includes a nozzle plate made of a silicon single crystal substrate and formed with a plurality of nozzles, an ink cavity (pressure chamber) made of a silicon single crystal substrate and communicating with the nozzles, and an ink reservoir. A cavity plate in which a (common liquid chamber) is formed and a glass substrate on which individual electrodes are disposed are attached, and the ink cavity and the ink reservoir are connected to an ink supply path formed in the nozzle plate. There is one that communicates with each other (see, for example, Patent Document 1).

  Here, for example, a plurality of nozzle plates are integrally formed on a silicon wafer, and finally formed by dividing the silicon wafer. That is, after a plurality of nozzles and ink supply paths corresponding to each nozzle plate are formed on the silicon wafer by etching, the silicon wafer is divided into a plurality of nozzle plates.

  When a plurality of nozzles, ink supply paths, and the like are formed on a silicon wafer by etching as described above, the depth varies within the surface of the silicon wafer, and the ink jet recording head having the above-described configuration is obtained. In addition, there is a problem that the ink discharge characteristics vary among the heads. Further, since the variation in the ejection characteristics is relatively large, there is a problem that the yield is lowered.

  Such a problem naturally exists not only in the ink jet recording head but also in other liquid ejecting heads.

Japanese Patent Laid-Open No. 11-198386 (Claims, FIG. 1 etc.)

  In view of such circumstances, it is an object of the present invention to provide a method of manufacturing a liquid jet head that can substantially uniform discharge characteristics.

A first aspect of the present invention that solves the above problem is that a plurality of pressure chambers that communicate with a nozzle from which droplets are discharged, a common liquid chamber that is common to the plurality of pressure chambers, a single flow path section, and a plurality of sub-channels are provided. And a supply port portion for supplying the liquid in the common liquid chamber to the pressure chamber, and at least the supply port portion is formed on a flow path substrate made of a silicon single crystal substrate. A method of manufacturing a liquid jet head, comprising: etching a silicon wafer on which a plurality of the flow path substrates are integrally formed for a predetermined time using a predetermined protective film as a mask; An etching step of simultaneously forming the supply port portion corresponding to the above, and a dividing step of dividing the silicon wafer on which the supply port portion is formed into a plurality of flow path substrates, and the etching In the step, the silicon wafer is substantially adjusted by adjusting at least one of a width and a length of the narrow groove constituting the branch channel portion of the supply port portion according to an in-plane position of the silicon wafer. The liquid jet head manufacturing method is characterized in that the flow path resistance of each supply port formed is made uniform.
In the first aspect, variation in flow path resistance of each supply port is suppressed regardless of the in-plane position of the silicon wafer. Thereby, the ejection characteristics of each head can be made uniform.

According to a second aspect of the present invention, in the first aspect, in the etching step, at least one of a width and a length of the protective film in a region corresponding to the columnar protrusion defining each narrow groove is adjusted. The present invention is directed to a method for manufacturing a liquid jet head.
In the second aspect, the shape (width or length) of the narrow groove of each supply port can be adjusted very easily and reliably.

According to a third aspect of the present invention, in the first or second aspect, the silicon wafer is anisotropically dry-etched by inductively coupled plasma (ICP) discharge in the etching step. Is in the way.
In the third aspect, when anisotropic dry etching by IPC discharge is performed, variation in flow resistance is particularly likely to occur. However, by adjusting the width or length of the narrow groove, the flow is relatively easy and reliable. Variation in road resistance can be suppressed.

According to a fourth aspect of the present invention, in any one of the first to third aspects, at least one of the width and the length of the narrow groove formed in the peripheral portion of the silicon wafer is changed to the central portion of the silicon wafer. According to another aspect of the invention, there is provided a method of manufacturing a liquid ejecting head, wherein the liquid ejecting head is substantially shorter than that of the narrow groove to be formed.
In the fourth aspect, it is possible to more reliably suppress variations in flow path resistance of the supply port portion.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the flow path substrate is a nozzle plate having the nozzle together with the supply port portion. It is in.
In the fifth aspect, it is possible to manufacture a liquid jet head that is relatively small and has excellent ink ejection characteristics.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is a schematic perspective view of an ink jet recording head which is an example of a liquid ejecting head, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a schematic view showing an ink supply port portion. The illustrated ink jet recording head is a so-called electrostatic drive head, and includes a cavity substrate 10 and a nozzle plate 20 and an electrode substrate 30 that are respectively bonded to both surfaces of the cavity substrate 10.

  The cavity substrate 10 is made of, for example, a silicon single crystal substrate having a plane orientation (100) or (110), and a plurality of pressure chambers (cavities) 11 opened on one surface side thereof are arranged in parallel in the width direction. In the present embodiment, as shown in FIG. 2, the cavity substrate 10 is formed with two rows in which a plurality of pressure chambers 11 are arranged in parallel. Further, the cavity substrate 10 is formed with a common ink chamber 12 serving as an ink chamber common to the pressure chambers 11 of each row, and the common ink chamber 12 is connected to each pressure chamber via an ink supply port portion described later. 11 is communicated. An ink supply hole 13 for supplying ink to the common ink chamber 12 is formed in the bottom wall of the common ink chamber 12. The cavity substrate 10 is formed with a through hole 14 on the outside of the common ink chamber 12 for exposing an individual terminal portion connected to an individual electrode described later. The through hole 14 may be continuously formed up to the end surface of the cavity substrate 10 opposite to the common ink chamber 12.

  Note that the bottom wall of each pressure chamber 11 functions as a diaphragm 15 for causing a pressure change in the pressure chamber 11 and serves as a common electrode for generating an electrostatic force that displaces the diaphragm 15. Doubles as In the vicinity of the through hole 14 of the cavity substrate 10, a common terminal portion 16 is formed which is exposed in an exposure hole (described later) of the nozzle plate 20 and connected to a drive wiring (not shown).

  Similarly to the cavity substrate 10, the nozzle plate 20 is made of a silicon single crystal substrate having a plane orientation (100) or (110), and a plurality of nozzles 21 communicating with the pressure chambers 11 are formed. The nozzle plate 20 is bonded to the opening surface side of the cavity substrate 10 to form one surface of the pressure chamber 11 and the common ink chamber 12. A nozzle step portion 22 is formed on the surface of the nozzle plate 20 opposite to the cavity substrate 10 by removing a part in the thickness direction over a region corresponding to the nozzle 21.

  Here, each nozzle 21 is provided on the ink droplet ejection side and has a substantially circular small-diameter portion 21a that opens into the nozzle step portion 22, and has a diameter larger than that of the small-diameter portion 21a. The large-diameter portion 21 b communicates with the chamber 11. All the nozzles 21 (small-diameter portions 21a) are opened in the nozzle step portion 22, and in this embodiment, the surface of the nozzle plate 20 in the nozzle step portion 22 is a nozzle surface.

  In addition, on the joint surface of the nozzle plate 20 with the cavity substrate 10, an ink supply that communicates each of the pressure chambers 11 and the common ink chamber 12 with a region corresponding to the boundary between the pressure chamber 11 and the common ink chamber 12. A mouth portion 23 is formed. As shown in FIG. 3, a plurality of columnar protrusions 24 are juxtaposed at the central portion of the ink supply port 23, that is, the pressure chamber 11, the common ink chamber 12, and the intermediate portion, and are defined by the columnar protrusions 24. A diversion channel portion 26 is formed that includes a plurality of narrow grooves 25. The ink supply port portion 23 according to the present embodiment is constituted by the branch channel portion 26 and the single channel portions 27 on both sides thereof.

  The nozzle plate 20 has an exposure hole 28 that communicates with the through hole 14 of the cavity substrate 10 at a position corresponding to the outside of the common ink chamber 12 and exposes the common terminal portion 16 together with the individual terminal portion described later. ing. The exposure hole 28 may be continuously formed up to the end surface opposite to the common ink chamber 12, as in the case of the through hole 14.

  Further, a water / oil repellent film 29 made of a water / oil repellent material made of, for example, a fluorine-containing silane coupling compound is formed on the surface of the nozzle plate 20, in the present embodiment, in the nozzle step portion 22. . Thereby, adhesion of ink droplets to the surface (nozzle surface) of the nozzle plate 20 is suppressed.

  On the other hand, the electrode substrate 30 is made of a glass substrate such as borosilicate glass having a thermal expansion coefficient close to that of a silicon single crystal substrate, and is bonded to the surface of the cavity substrate 10 on the vibration plate 15 side. In the region of the electrode substrate 30 facing the diaphragm 15, a recess 31 is formed corresponding to each pressure chamber 11. In addition, an ink introduction hole 32 communicating with the ink supply hole 13 is formed in the electrode substrate 30 at a position corresponding to the ink supply hole 13 of the cavity substrate 10. The common ink chamber 12 is filled with ink from an ink tank (not shown) through the ink introduction hole 32 and the ink supply hole 13.

  In addition, individual electrodes 33 for generating an electrostatic force that displaces the diaphragm 15 are disposed in the respective recesses 31 in a state in which a predetermined interval is secured between the individual electrodes 33. In the recess 31, an individual terminal portion 34 to which a drive wiring (not shown) is connected is formed in a region facing the through hole 14 of the cavity substrate 10, and the individual terminal portion 34 and each individual electrode 33 are connected to each other. Are connected by a lead electrode 35. Although not shown, each individual electrode 33 and the lead electrode 35 are sealed with an insulating film, and a driving voltage pulse is applied between the individual terminal portion 34 and the common terminal portion 16 via a connection wiring. For this purpose, an oscillation circuit is connected.

  In such an ink jet recording head, when a driving voltage is applied between the individual electrode 33 and the diaphragm 15 (cavity substrate 10) by the oscillation circuit, the ink jet recording head is generated in a gap between the individual electrode 33 and the diaphragm 15. When the diaphragm 15 is bent and deformed by the electrostatic force toward the individual electrode 33 side, the volume of the pressure chamber 11 is expanded and the application of the drive voltage is released, the diaphragm 15 returns to the original state, and the volume of the pressure chamber 11 is increased. Contracts. Then, due to the pressure change in the pressure chamber 11 generated at this time, a part of the ink in the pressure chamber 11 is ejected as an ink droplet from the nozzle 21.

  Here, the manufacturing method of the nozzle plate which is a flow-path board | substrate which concerns on this embodiment is demonstrated. As shown in FIG. 4, a plurality of nozzle plates 20 are integrally formed on a nozzle plate wafer 200, which is a single silicon wafer, and finally divided into chip sizes. 5 and 6 are cross-sectional views in a direction orthogonal to the nozzle row, and FIG. 7 shows a nozzle plate 20A formed at the center of the nozzle plate wafer 200 and nozzles formed at the peripheral edge. It is a figure which shows the mask shape of the ink supply opening part corresponding to each of plate 20C and the nozzle plate 20B (refer FIG. 4) formed in an intermediate part (area | region between a center part and a peripheral part).

  First, as shown in FIG. 5A, for example, a nozzle plate wafer 200 which is a silicon wafer having a thickness of 180 μm is thermally oxidized to form a protective film 201 made of an oxide film made of silicon dioxide on the surface. Form. Next, as shown in FIG. 5B, the protective film 201 on one side of the nozzle plate wafer 200 is etched with, for example, ammonium fluoride, so that the small diameter portion is formed in the region where the nozzle 21 is formed. An opening 202 having substantially the same diameter as 21a is formed. An opening 203 having a predetermined shape is also formed in a region where the exposure hole 28 for exposing the individual terminal portion is formed. In the present embodiment, the opening 203 is formed only at the periphery of the region where the exposure hole 28 is formed. Next, as shown in FIG. 5C, the protective film 201 is further half-etched to form a recess 204 having a diameter substantially the same as the large diameter portion 21b and a predetermined depth in the region where the nozzle 21 is formed. . In addition, a recess 205 having a predetermined depth and having substantially the same opening shape as the ink supply port portion 23 is formed in a region where the ink supply port portion 23 is formed. That is, the recess 205 having a predetermined depth is formed in the region where the ink supply port 23 is formed, leaving the protective film 201a in the region where the columnar protrusion 24 is formed.

  Here, in the present embodiment, when such a recess 205 is formed, the protective film of the portion corresponding to the opening shape of the recess 205, that is, the columnar protrusion 24, according to the in-plane position of the nozzle plate wafer 200. The shape (size) of 201a is adjusted. For example, in the present embodiment, the protective film 201a is formed to have a longer length toward the peripheral edge side of the nozzle plate wafer 200. That is, as shown in FIG. 7, an ink supply port 23A corresponding to the nozzle plate 20A at the center of the nozzle plate wafer 200, an ink supply port 23B corresponding to the intermediate nozzle plate 20B, and a peripheral portion In three stages with the nozzle supply port 23C corresponding to the nozzle plate 20C, the protective films 201a having different lengths are left.

  Next, as shown in FIG. 5D, the groove portions 206 and 207 are formed by etching the nozzle plate wafer 200 using the protective film 201 as a mask. For example, in this embodiment, the groove portions 206 and 207 are formed to have substantially the same depth as the small diameter portion 21a of the nozzle 21 by anisotropic dry etching of the nozzle plate wafer by inductively coupled plasma (ICP) discharge. .

  Next, as shown in FIG. 5E, the protective film 201 on the surface of the nozzle plate wafer 200 is etched with a hydrofluoric acid aqueous solution, and a part of the thickness direction is removed to correspond to the recesses 204 and 205. Openings 208 and 209 are formed in the portions to be formed. That is, the entire protective film 201 is removed with a uniform thickness until the protective film 201 in the recesses 204 and 205 is completely removed.

  Then, as shown in FIG. 5 (f), the nozzle plate wafer 200 is again anisotropically etched by inductively coupled plasma (ICP) discharge through the openings 203, 208, and 209. At this time, the nozzle plate wafer 200 is etched while the surface shape is maintained. Therefore, by etching the nozzle plate wafer 200 to the same depth as the large diameter portion 21b, the nozzle 21 composed of the small diameter portion 21a and the large diameter portion 21b is formed in a portion corresponding to the opening 208. Further, an ink supply port portion 23 including a single flow path portion 27 and a diversion flow path portion 26 is formed in a region corresponding to the opening 209. At the same time, the groove 207 is formed deeper.

  Here, since the etching rate of the silicon wafer that is the nozzle plate wafer 200 differs depending on the in-plane position, for example, the depth of the ink supply port 23 or the like varies greatly depending on the in-plane position of the nozzle plate. Specifically, since the etching rate is faster toward the peripheral edge side of the nozzle plate wafer 200, the ink supply port 23 is formed deeper toward the peripheral edge side. Further, when the ink supply port 23 is formed by anisotropic etching by inductively coupled plasma (IPC) discharge as in the present embodiment, such a variation in depth appears particularly remarkably. Then, due to the difference in the depth of the ink supply port portion 23, the ink discharge characteristics in each head vary.

  However, in the present embodiment, the portion of the protective film 201a corresponding to each columnar protrusion 24 corresponds to the in-plane position of the nozzle plate wafer 200, that is, the depth of the ink supply port portion 23 to be formed. The length was adjusted to substantially adjust the length of the narrow groove 25. Therefore, although the depth of each ink supply port 23 varies depending on the in-plane position of the nozzle plate wafer 200, the flow path resistance of each ink supply port 23 is made uniform.

  Therefore, if an ink jet recording head is formed using the nozzle plates 20 formed on the same nozzle plate wafer 200 in this way, there is at least a variation in ejection characteristics due to the flow path resistance of the ink supply port 23. It is reliably suppressed, and the ejection characteristics at each head are made uniform. In addition, since the discharge characteristics are made uniform in this way, the variation in print quality is reduced and the yield is improved.

  After forming the ink supply ports 23 and the like in this way, as shown in FIG. 6A, the protective film 201 on the surface of the nozzle plate wafer 200 is once peeled off with a hydrofluoric acid aqueous solution. Next, as shown in FIG. 6B, the nozzle plate wafer 200 is thermally oxidized, and a protective film 211 made of an oxide film is formed again on the entire surface including the inside of the nozzle 21 and the like. Next, as shown in FIG. 6C, the surface of the nozzle plate wafer 200 opposite to the ink supply port 23, that is, the protective film 211 on the nozzle surface side is etched with, for example, ammonium fluoride. As a result, openings 212 and 213 are formed in regions where the nozzle step portion 22 and the exposure hole 28 are formed. Then, as shown in FIG. 6D, the nozzle step portion 22 is formed by anisotropically etching the nozzle plate wafer 200 with, for example, a potassium hydroxide solution (KOH) using the protective film 211 as a mask. And the exposure hole 28 is substantially penetrated.

  Further, after the nozzle step portion 22 and the like are formed in this way, as shown in FIG. 6E, the protective film 211 on the surface of the nozzle plate wafer 200 is completely peeled off with a hydrofluoric acid aqueous solution or the like. As a result, the nozzle 21 opens into the nozzle step portion 22 and the exposure hole 28 is completely penetrated. Thereafter, although not shown, the nozzle plate wafer 200 is thermally oxidized again to form an oxide film serving as an ink protective film on the inner surface of the nozzle 21 and the like, and is cut into a predetermined size by dicing or the like. As a result, the nozzle plate 20 is formed.

  Although one embodiment of the present invention has been described above, of course, the present invention is not limited to such an embodiment. For example, in this embodiment, the flow path resistance of the ink supply port portion 23 is adjusted by the length of the columnar protrusion 24 (thin groove 25), but the present invention is not limited to this, and the columnar protrusion 24 (thin groove 25). The flow path resistance of the ink supply port 23 may be adjusted according to the width of the ink or the number of columnar protrusions 24 (thin grooves 25). In any case, the flow path resistance of each ink supply port portion 23 can be made relatively easy by simply adjusting the shape (size) of the protective film 201 a corresponding to the columnar protrusion 24. In the present embodiment, the structure in which the ink supply port is formed in the nozzle plate is exemplified. However, the present invention is applicable to a head having any configuration such as a configuration in which the ink supply port is formed in the cavity substrate. can do.

  Furthermore, in the present embodiment, the present invention has been described by taking an electrostatic drive type ink jet recording head as an example, but the present invention is not limited to this, for example, a method of ejecting ink droplets by displacement of a piezoelectric element, or In addition, the ink jet recording head of any system can be employed, such as a system in which ink droplets are ejected by heating ink with a heating element or the like. Of course, the present invention can be applied not only to an ink jet recording head that ejects ink droplets but also to a liquid ejecting head that ejects all other droplets. Other liquid ejecting heads include, for example, color material ejecting heads used for manufacturing color filters such as liquid crystal displays, electrode material ejecting heads used for forming electrodes such as organic EL displays and FEDs (surface emitting displays), and biochips. Examples thereof include a bio-organic matter ejecting head used for manufacturing.

1 is a schematic perspective view of a recording head according to an embodiment. FIG. 3 is a cross-sectional view of a recording head according to an embodiment. FIG. 3 is a schematic diagram illustrating an ink supply port portion of a recording head according to an embodiment. It is the schematic explaining the wafer for nozzle plates. It is sectional drawing which shows the manufacturing process of the recording head which concerns on one Embodiment. It is sectional drawing which shows the manufacturing process of the recording head which concerns on one Embodiment. It is the schematic which shows the shape of the protective film corresponding to an ink supply port part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Cavity board | substrate, 11 Pressure chamber, 12 Common ink chamber, 13 Ink supply hole, 14 Through-hole, 15 Diaphragm, 16 Common terminal part, 20 Nozzle plate, 21 Nozzle, 22 Nozzle level | step difference part, 23 Ink supply port part, 24 Columnar protrusion, 25 narrow groove, 26 minute flow path part, 27 single flow path part, 28 exposed hole, 29 water / oil repellent film, 30 electrode substrate, 31 recess, 32 ink introduction hole, 33 individual electrode, 34 individual terminal part, 35 Lead electrode, 200 Nozzle plate wafer

Claims (5)

The common liquid chamber is composed of a plurality of pressure chambers communicating with a nozzle from which liquid droplets are discharged, a common liquid chamber common to the plurality of pressure chambers, and a single channel portion and a branch channel portion including a plurality of narrow grooves. And a supply port for supplying the liquid to the pressure chamber, and at least the supply port is a method for manufacturing a liquid jet head formed on a flow path substrate made of a silicon single crystal substrate,
Etching a silicon wafer on which a plurality of flow path substrates are integrally formed for a predetermined time using a predetermined protective film as a mask, simultaneously forms the supply port portions corresponding to the plurality of flow path substrates on the silicon wafer. And at least a dividing step of dividing the silicon wafer on which the supply port portion is formed to form a plurality of flow path substrates, and the etching step depends on an in-plane position of the silicon wafer. By substantially adjusting at least one of the width and length of the narrow groove constituting the branch channel portion of the supply port portion, the flow channel resistance of each supply port portion formed in the silicon wafer is made uniform. A method of manufacturing a liquid ejecting head, characterized in that: 2. The liquid jet head manufacturing method according to claim 1, wherein, in the etching step, at least one of a width and a length of the protective film in a region corresponding to the columnar protrusion defining each narrow groove is adjusted. Method. 3. The method of manufacturing a liquid jet head according to claim 1, wherein in the etching step, the silicon wafer is anisotropically dry etched by inductively coupled plasma (ICP) discharge. 4. The method according to claim 1, wherein at least one of the width and the length of the narrow groove formed at the peripheral edge of the silicon wafer is set to be larger than that of the narrow groove formed at the center of the silicon wafer. A method of manufacturing a liquid jet head, characterized by being substantially shortened. 5. The method of manufacturing a liquid jet head according to claim 1, wherein the flow path substrate is a nozzle plate having the nozzle together with the supply port portion.

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