JP2007326231A - Manufacturing method for nozzle plate, manufacturing method for liquid droplet ejection head and manufacturing method for liquid droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a nozzle plate in which a stable ink ejection characteristic is achieved by forming nozzle holes of a high working precision while manufacturing processes required for manufacturing of the nozzle plate are reduced, and to provide a manufacturing method for a liquid droplet ejection head and a manufacturing method for a liquid droplet ejector. <P>SOLUTION: In the nozzle plate, the nozzle hole consisting of a first nozzle hole 6 and a tapered second nozzle hole 7 which communicates with the first nozzle hole 6 and has a diameter made gradually larger than that of the first nozzle hole 6 is formed in a silicon substrate. Patterning of a part 7a to be the second nozzle hole 7 is carried out in the form of a plurality of rings increased in diameter from a center axis of the second nozzle hole 7 towards the outer periphery, and simultaneously with patterning of a part 6a to be the first nozzle hole 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a nozzle plate in which nozzle holes for discharging ink droplets are formed, a method of manufacturing a droplet discharge head, and a method of manufacturing a droplet discharge device, and in particular, nozzle holes with high processing accuracy while reducing the number of manufacturing steps. The present invention relates to a method for manufacturing a nozzle plate, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device.

  In recent years, micro electro mechanical systems (MEMS) that process silicon or the like to form microelements or the like have rapidly advanced. The microfabricated elements formed by this microfabrication technology include, for example, a droplet discharge head (inkjet head), a micropump, and an optical variable filter used in a recording (printing) apparatus such as a droplet discharge type printer. There are electrostatic actuators such as motors, pressure sensors and the like.

  Among these, a method of discharging ink droplets of a droplet discharge device (inkjet recording device) includes a method using an electrostatic force as a driving means, a method using a piezoelectric vibrator as a driving means, and a heating element as a driving means. There are methods to use. Among them, a droplet discharge device that discharges ink droplets by using electrostatic force in the driving means is particularly excellent in that the chip size is small and the density is high, the printing performance is high, and the life is extended. ing.

  An inkjet head mounted on such a droplet discharge device generally has a nozzle plate formed with a plurality of nozzle holes for discharging ink droplets, and is joined to the nozzle plate and communicates with the nozzle holes. And a cavity plate formed with an ink flow path such as a discharge chamber and a reservoir, and configured to discharge ink droplets from selected nozzle holes by applying pressure to the discharge chamber by a driving unit.

  In addition, for the ink jet head configured as described above, there is an increasing demand for higher quality such as printing and image quality, and there is also a strong demand for higher nozzle hole density and improved ink ejection performance. . Against this background, various devices have been proposed for the nozzle plate of an inkjet head. To improve ink discharge performance, adjust the flow resistance of the ink droplets at the nozzle holes provided in the nozzle plate, and adjust the thickness of the nozzle plate to achieve the optimal nozzle length. Is desirable.

  As such, “in the nozzle forming method of an injection device that forms a nozzle by etching a silicon single crystal substrate, a resist film is formed on the surface of the silicon single crystal substrate, and the rear end side of the nozzle is formed. A first opening pattern is formed by removing the corresponding part of the resist film, and a second opening smaller than the first opening pattern is formed by removing the resist film of the part corresponding to the tip side of the nozzle. A pattern is formed, and anisotropic dry etching is performed on the exposed portion of the surface of the silicon single crystal substrate exposed by the first and second opening patterns to form a stepped shape from the rear end side toward the front end side. A nozzle forming method for an injection device characterized in that a nozzle having a smaller cross section is formed is proposed (for example, see Patent Document 1).

  In this nozzle forming method, anisotropic dry etching using ICP (Inductively Coupled Plasma) discharge is performed from one surface of a silicon substrate to thereby form a first cylindrical nozzle portion having a different inner diameter for constituting the nozzle portion. (Nozzle hole injection port portion) and the second cylindrical nozzle portion (nozzle hole introduction port portion) are formed in two stages, and then a part of the nozzle surface is dug down by anisotropic wet etching from the opposite surface. A method of adjusting the length is adopted.

  In addition, “a nozzle pattern corresponding to a nozzle is formed on one surface of a silicon substrate, a pattern corresponding to an ink inlet hole is formed on the other surface, and anisotropic dry etching is performed on one surface to form a nozzle. In addition, an isotropic etching having a certain degree of anisotropy is performed on the other surface to form an ink inlet hole, and after removing the etching mask, a thermal oxide film is formed. A “manufacturing method” has been proposed (see, for example, Patent Document 2). In this inkjet head nozzle plate manufacturing method, a silicon substrate is polished to a desired thickness in advance, and then dry etching is performed on both sides of the silicon substrate to form nozzle hole injection port portions and inlet port portions. is doing.

  Furthermore, a “nozzle plate having a knife edge-shaped blow-off edge chamfered around the blow-out opening of the tapered nozzle hole provided in the substrate made of the silicon single crystal wafer” has been proposed (for example, Patent Documents). 3). In this nozzle plate, anisotropic wet etching is performed on one side to form a nozzle hole introduction port portion (tapered nozzle hole) that expands in a pyramid shape.

  In this case, the nozzle part of the nozzle hole is a cylindrical nozzle having a constant cross section, and the inlet part of the nozzle hole on the back side is a tapered nozzle that expands in a conical shape or a pyramid shape, thereby forming a cylindrical shape as a whole. Compared to the case where nozzles are used, the direction of ink pressure applied to the nozzles from the ink cavity side can be aligned with the ink axis direction, eliminating variations in the flying direction, eliminating scattering of ink droplets, and variations in ink droplet volume. Suppressed and realized stable ink ejection characteristics.

Japanese Patent Laid-Open No. 11-28820 (page 4, FIGS. 3 and 4) Japanese Patent Laid-Open No. 9-57981 (page 3 and FIG. 1) Japanese Patent Laid-Open No. 56-133505 (first page and FIG. 1)

  The nozzle hole forming method described in Patent Document 1 has a problem in that the ejection surface on which the nozzle hole opens is a bottom surface of a concave portion that is deeply lowered one step from the substrate surface, resulting in the flying bending of ink droplets. . Also, when paper dust or ink that causes clogging of the nozzle holes adheres to the bottom surface of the recess that is the discharge surface, wiping to wipe the bottom surface of the recess with a rubber piece or felt piece to eliminate them There was also a problem that the work would be difficult.

  In the manufacturing method of the nozzle plate for an ink jet head described in Patent Document 2 and the nozzle plate described in Patent Document 3, as the density of the ink jet head increases, the thickness of the silicon nozzle plate substrate must be further reduced. Such a silicon substrate has a problem that it is easily broken during the manufacturing process and becomes expensive. In addition, since the injection port portion of the nozzle hole and the introduction port portion of the nozzle hole are formed after separately patterning on both surfaces of the substrate, there is a problem that double-sided alignment must be performed with high accuracy.

  If alignment is not performed with high accuracy, an axial deviation occurs between the central axis of the nozzle hole injection port and the central axis of the nozzle hole introduction port, which causes the ink ejection direction to bend. It is. Furthermore, the influence of alignment accuracy has become non-negligible as the density of inkjet heads increases. In other words, if the ink ejection direction bends in each ink hole, the overall ink ejection performance is deteriorated and the demand for stable ink ejection characteristics cannot be met.

  In addition, in the case of the manufacturing method of the nozzle plate for an ink jet head described in Patent Document 2, cooling is performed with helium gas or the like from the back surface of the substrate so as to stabilize the processing shape during dry etching processing. There was a problem that helium gas and the like leaked during penetration. This problem is that when helium gas or the like leaks, dry etching becomes impossible due to the influence of the helium gas or the like.

  In order to solve this problem, for example, a double-sided adhesive having a part that becomes a nozzle hole in a silicon substrate in advance and having a release layer on which one side of the adhesive layer can be easily lowered by an stimulus such as ultraviolet rays or heat. After the sheets are bonded together, the silicon substrate may be thinned by grinding or etching to open the nozzle holes. Alternatively, the nozzle holes may be opened after the resin is attached to a support substrate such as quartz glass. However, when such a method is adopted, the number of steps required for manufacturing the nozzle plate must be further increased.

  The present invention has been made to solve the above-described problems. A nozzle that has a high processing accuracy while reducing the number of manufacturing steps required to manufacture the nozzle plate and realizes stable ink ejection characteristics. It is an object of the present invention to provide a method for manufacturing a plate, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device.

  The method of manufacturing a nozzle plate according to the present invention includes a first nozzle hole, a tapered second nozzle that is in communication with the first nozzle hole and has a gradually larger diameter than the first nozzle hole. A method of manufacturing a nozzle plate for forming a nozzle hole comprising a plurality of holes, wherein a plurality of rings are formed such that patterning of a portion to be a second nozzle hole increases in diameter from the central axis of the second nozzle hole toward the outer periphery. It is characterized in that it is performed simultaneously with the patterning of the portion that becomes the first nozzle hole as a shape.

  Therefore, the part to be the first nozzle hole and the part to be the second nozzle hole can be patterned at the same time, and the number of manufacturing steps can be reduced as compared with the patterning separately. Further, since patterning can be performed collectively on the portion to be the first nozzle hole and the portion to be the second nozzle hole, an etching mask for dry etching to be performed later can also be formed collectively. That is, the number of patterning steps can be reduced, and the number of steps required for forming an etching mask can be reduced.

  The method for manufacturing a nozzle plate according to the present invention is characterized in that patterning is performed so that walls are formed concentrically between the ring shapes. In this way, the nozzle hole can be formed without the center axis of the first nozzle hole deviating from the center axis of the second nozzle hole. Therefore, stable ink ejection characteristics can be realized, and a highly reliable droplet ejection head can be provided.

  The method for manufacturing a nozzle plate according to the present invention is characterized in that ribs are formed in each ring shape and patterning is performed so that the silicon substrate is exposed at a predetermined interval. Accordingly, the patterning of the portion that becomes the second nozzle hole can be performed without being limited to a complete ring shape. That is, the portion that becomes the second nozzle hole may be patterned in consideration of the characteristics of the microloading effect that is a phenomenon peculiar to the dry etching apparatus.

  The nozzle plate manufacturing method according to the present invention is characterized in that the ring width between the ring shapes is gradually narrowed from the central axis toward the outer periphery. By doing so, the microloading effect that is a phenomenon peculiar to the dry etching apparatus is used, that is, the etching depth becomes shallower as the opening becomes narrower. A nozzle hole can be formed.

  The manufacturing method of the nozzle plate according to the present invention is characterized in that the central axis is the same as the central axis of the first nozzle hole. Therefore, alignment adjustment for eliminating the shift of the central axis between the first nozzle hole and the second nozzle hole becomes unnecessary. That is, since the ink discharge direction is not bent and stable ink discharge characteristics can be realized, a highly reliable droplet discharge head can be provided.

  In the method for manufacturing a nozzle plate according to the present invention, after the portion to be the first nozzle hole and the portion to be the second nozzle hole are dry-etched, the surface of the silicon substrate is oxidized to form the first nozzle hole. The oxide film formed on the side surface and the bottom surface of the portion that becomes the portion and the second nozzle hole is removed. In other words, since the wall formed between the ring shapes of the portion serving as the second nozzle hole is all calculated to be a thickness that becomes an oxide film, the taper-shaped first film with high processing accuracy can be obtained simply by removing the oxide film. Two nozzle holes can be formed.

  The method for manufacturing a nozzle plate according to the present invention is characterized in that the dry etching is anisotropic dry etching by ICP discharge. Thus, since the nozzle hole is formed by anisotropic dry etching, it is possible to form a nozzle hole with high processing accuracy. In other words, it is possible to provide a droplet ejection head that eliminates the flight bending of ink droplets and has high stability and reliability.

  The method for manufacturing a nozzle plate according to the present invention includes laminating a support substrate to a surface of a silicon substrate on which a second nozzle hole is formed, and thinning the opposite surface of the silicon substrate to which the support substrate is adhered. The first nozzle hole is opened from the side of the silicon substrate, the surface of the silicon substrate is subjected to water repellent treatment, and then the support substrate is peeled off from the silicon substrate. Thus, since the support substrate is peeled from the silicon substrate after the water repellent treatment, the water repellent film formed on the nozzle hole portion is not peeled off together.

  The method for manufacturing a nozzle plate according to the present invention is characterized in that the silicon substrate and the support substrate are bonded together in a vacuum. In other words, by bonding the silicon substrate and the support substrate in a vacuum, it becomes possible to bond the silicon substrate and the support substrate without causing bubbles or the like to accumulate. Accordingly, since no bubbles remain between the substrates, the surface of the silicon substrate becomes smooth, and variations in the thickness of the silicon substrate are eliminated.

  In the method of manufacturing a droplet discharge head according to the present invention, a liquid flow path including a plurality of discharge chambers in which a bottom wall forms a vibration plate to collect and discharge droplets is formed on any of the nozzle plates described above. It is characterized in that a bonded substrate formed by the formed silicon substrate and a glass substrate on which an individual electrode for driving the vibrating plate is formed facing the vibrating plate with a gap is bonded. Therefore, it is possible to manufacture a droplet discharge head having the above effects and high ink droplet discharge performance.

  A method for manufacturing a droplet discharge device according to the present invention is characterized in that a droplet discharge device is manufactured by applying the method for manufacturing a droplet discharge head described above. Accordingly, it is possible to manufacture a droplet discharge device having the above-described effects and high ink droplet discharge performance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing a state in which a droplet discharge head 100 according to an embodiment of the present invention is disassembled. FIG. 2 is a longitudinal sectional view showing a sectional configuration of the droplet discharge head 100. The droplet discharge head 100 is a face eject type liquid that discharges droplets from nozzle holes provided on the surface side of a nozzle plate as a representative of electrostatic drive type electrostatic actuators driven by electrostatic force. A droplet discharge head is shown as an example. The configuration and operation of the droplet discharge head 100 will be described with reference to FIGS.

  As shown in FIG. 1, the droplet discharge head 100 is configured as a three-layer structure in which a silicon cavity substrate 1, a glass substrate 2, and a nozzle plate 3 are joined together in order. . That is, the cavity substrate 1 is sandwiched between the glass substrate 2 and the nozzle plate 3 from above and below. Here, a case where the droplet discharge head 100 has a three-layer structure will be described as an example, but the present invention is not limited to this. For example, the droplet discharge head 100 may have a four-layer structure including a glass substrate, a cavity substrate, a reservoir substrate, and a nozzle plate.

[Nozzle plate 3]
The nozzle plate 3 is preferably composed of a silicon single crystal substrate (hereinafter simply referred to as a silicon substrate) so that predetermined processing as will be described later can be easily performed. For example, the nozzle plate 3 may be configured with a silicon substrate having a thickness of about 180 μm (micrometer) as a main material. The nozzle plate 3 is bonded to the cavity substrate 1 at its lower surface (bonding surface 11 to the cavity substrate 1).

  The nozzle plate 3 includes, for example, a cylindrical first nozzle hole 6, a nozzle hole 8 that communicates with the first nozzle hole 6 and includes a funnel-shaped (tapered) second nozzle hole 7. Is formed. A plurality of nozzle holes 8 are formed so as to communicate with each discharge chamber 13 formed in the cavity substrate 1 described later. And from each nozzle hole 8 formed in the nozzle plate 3, droplets, such as ink transferred from each discharge chamber 13, are discharged outside.

  The first nozzle hole 6 and the second nozzle hole 7 constituting the nozzle hole 8 are formed with the same central axis. The first nozzle hole 6 is formed so as to open on the ink discharge surface 10 (the surface opposite to the bonding surface 11 with the cavity substrate 1), and the second nozzle hole 7 opens on the bonding surface 11. It is formed to do. The funnel-shaped second nozzle hole 7 is formed so that the nozzle diameter gradually increases toward the bonding surface 11 side. If the nozzle holes 8 are formed in this way, it is possible to expect an improvement in straightness when discharging droplets.

[Cavity substrate 1]
The cavity substrate 1 is made of, for example, a (110) plane silicon substrate having a thickness of about 50 μm, and has a discharge chamber (pressure chamber) 13 having a flexible bottom wall and acting as a deformable diaphragm 12. It is desirable to form a plurality of recesses. Further, in the cavity substrate 1, droplets that are discharged in common to the nozzle holes 8 are stored, and a recess serving as a reservoir 14 for supplying droplets such as ink to the discharge chambers 13, and the reservoir 14 and the discharge chambers. It is good to form the recessed part used as the narrow groove-shaped orifice 15 which makes 13 connect.

  The discharge chamber 13, the reservoir 14, and the orifice 15 are preferably formed by performing either or both of dry etching and anisotropic wet etching on a silicon substrate. The discharge chamber 13, the reservoir 14, and the orifice 15 function as a flow path for liquid droplets. Note that the plurality of discharge chambers 13 are formed in parallel from the front side to the back side in FIG. In the droplet discharge head 100, the reservoir 14 is formed from a single recess, and one orifice 15 is formed for each discharge chamber 13. The orifice 15 may be formed on the joint surface 11 of the nozzle plate 3.

The entire surface of the cavity substrate 1 has a thickness of 0.1 μm made of silicon oxide (SiO ₂ ) such as TEOS (Tetra Ethyl Orthosilicate: Tetraethoxysilane, ethyl silicate) by plasma CVD (Chemical Vapor Deposition) or thermal oxidation, for example. The insulating film 16 may be formed. The insulating film 16 serves to prevent dielectric breakdown and short circuit when the droplet discharge head 100 is driven.

  In addition, by forming the insulating film 16 on the entire surface of the cavity substrate 1, it also serves to prevent the cavity substrate 1 from being etched and corroded by droplets inside the discharge chamber 13 and the reservoir 14. Can do. Further, if the insulating film 16 is formed on the entire surface of the cavity substrate 1, the stress on the upper surface of the cavity substrate 1 and the stress on the lower surface of the cavity substrate 1 can be offset, and the warpage of the diaphragm 12 can be suppressed to be small. There is also an effect that can be done. Although the case where the insulating film 16 is made of silicon oxide is shown as an example, the present invention is not limited to this.

  The cavity substrate 1 is further formed with a common electrode 19 as an external electrode terminal of the cavity substrate 1, and a portion corresponding to a connection portion of the glass substrate 2 with an external device is opened as an electrode outlet 25. ing. The common electrode 19 serves as a terminal for supplying charges having a polarity opposite to that of the individual electrode 17 from the oscillation circuit 22 (see FIG. 2) to the diaphragm 12. The discharge chamber 13 and the reservoir 14 formed in the cavity substrate 1 have a sawtooth shape because they are formed by performing anisotropic wet etching on a silicon substrate having a (110) orientation. Further, the reservoir 14 of the cavity substrate 1 is provided with an ink supply port 18 so as to communicate with the ink supply port 18 provided on the glass substrate 2.

[Glass substrate 2]
The glass substrate 2 has a thickness of about 1 mm and is bonded to the diaphragm 12 side of the cavity substrate 1. For the glass to be the glass substrate 2, for example, borosilicate heat-resistant hard glass may be used. In the glass substrate 2, a plurality of recesses 9 having a depth of about 0.2 μm are formed by etching so as to face each discharge chamber 13 formed in the cavity substrate 1. Since the pattern of the recess 9 is provided with the individual electrodes (electrodes) 17 therein, it is preferable that the pattern be formed slightly larger than those shapes.

  As the material of the individual electrode 17, transparent ITO (Indium Tin Oxide) doped with tin oxide as an impurity is used, and for example, an ECR (Electron Cyclotron Resonance) sputtering method is used to a thickness of 0.1 μm. To form a film. Thus, when the individual electrode 17 is made of ITO, there is an advantage that since it is transparent, it can be easily confirmed whether or not it is discharged, and an equipotential contact can be formed simultaneously. Although the case where the individual electrode 17 is made of ITO is shown as an example, the invention is not limited to this, and it may be made of a metal such as chromium.

  In addition, an ink supply port 18 communicating with the reservoir 14 is formed in the glass substrate 2. The ink supply port 18 is connected to a hole provided in the bottom wall of the reservoir 14 and is provided for supplying droplets such as ink to the reservoir 14 from the outside. When the cavity substrate 1 is made of single crystal silicon and the glass substrate 2 is made of borosilicate glass, the cavity substrate 1 and the glass substrate 2 can be joined by anodic bonding.

  When the cavity substrate 1 and the glass substrate 2 are joined, a gap (air gap) 20 is formed between the diaphragm 12 and the individual electrode 17 as an operation space of the diaphragm 12. The gap 20 is determined by the depth of the recess 9 and the thickness of the individual electrode 17 and the diaphragm 12 (insulating film 16). Since the gap 20 greatly affects the ejection characteristics of the droplet ejection head 100, strict accuracy control is required.

  The gap 20 is formed so as to have an elongated constant depth at a position facing each diaphragm 12. In addition to forming the recess 9 in the glass substrate 2, the gap 20 can be provided by forming a recess in the silicon substrate to be the cavity substrate 1 or by sandwiching a spacer. Further, the individual electrode 17 faces the diaphragm 12 with a gap of a constant interval and extends along the bottom surface of the gap 20 to the end of the glass substrate 2 (electrode extraction port 25). The electrode extraction port 25 is connected to the oscillation circuit 22 (see FIG. 2).

  The discharge chamber 13 formed in the cavity substrate 1 stores discharge liquid such as ink discharged from the nozzle hole 8, and uses the deformation of the diaphragm 12 constituting the bottom wall of the discharge chamber 13 to discharge. The pressure in the chamber 13 is increased and the droplet is ejected from the nozzle hole 8. In this embodiment, the diaphragm 12 is composed of a boron-doped layer obtained by diffusing high-concentration boron into a silicon substrate, and the surface is covered with an insulating film 16 made of silicon oxide such as TEOS.

In order to form the diaphragm 12 having a desired thickness, a boron-doped layer having the same thickness may be formed on the silicon substrate serving as the cavity substrate 1. This is because, when anisotropic wet etching of silicon is performed with an alkaline aqueous solution, when boron is used as a dopant, the etching rate becomes extremely small in a high concentration region (5 × 10 ¹⁹ atoms / cm ³ or more). Use it. That is, when the discharge chamber 13 and the reservoir 14 are formed by anisotropic wet etching, the thickness of the diaphragm 12 is obtained by using a so-called etching stop technique that utilizes an extremely small etching rate when the boron-doped layer is exposed. The volume of the discharge chamber 13 can be formed with high accuracy.

  FIG. 2 also shows a device (oscillation circuit 22) for operating the diaphragm 12 of the droplet discharge head 100. Here, an example is shown in which the common electrode 19 of the cavity substrate 1 and the individual electrode 17 of the glass substrate 2 are connected to the oscillation circuit 22 via a connection cable. For this connection cable, an FPC (not shown) can be used. The terminal of this FPC is mounted at a position corresponding to the electrode outlet 25 of the glass substrate 2 so as to electrically connect the common electrode 19 of the cavity substrate 1 and the individual electrode 17 of the glass substrate 2.

  The oscillation circuit 22 is connected to the individual electrode 17 via the FPC, and plays a role of controlling supply and stop of charge to the individual electrode 17. The oscillation circuit 22 oscillates at, for example, 24 kHz, and supplies electric charges by applying pulse potentials of 0 V and 30 V to the individual electrodes 17. The oscillation circuit 22 is preferably composed of an integrated circuit such as a driver IC. The oscillation circuit 22 may be provided inside the droplet discharge head 100 or may be provided outside.

  That is, when the oscillation circuit 22 is driven to oscillate and charges are supplied to the individual electrodes 17 to be positively charged, the diaphragm 12 is negatively charged and is attracted to the individual electrodes 17 by an electrostatic force and bends. As a result, the volume of the discharge chamber 13 increases. When the supply of electric charges to the individual electrode 17 is stopped, the diaphragm 12 returns to its original state, but the volume of the discharge chamber 13 at that time also returns to its original value. Recording (printing) is performed by landing on the recording paper to be recorded. Such a method is called pulling, but there is also a method called pushing that discharges droplets using a spring or the like. The cavity substrate 1 and the oscillation circuit 22 are also connected by FPC. However, it is preferable to connect a wire by inserting a wire into an oxide film window (not shown) opened in a part of the substrate by dry etching.

  FIG. 3 is a top view of the nozzle plate 3 as viewed from the ink ejection surface 10 side. As shown in FIG. 3, a plurality of first nozzle holes 6 are opened on the ink ejection surface 10 side of the nozzle plate 3. The second nozzle hole 7 is formed on the back side of the paper surface of each nozzle hole 6 in FIG. In addition, the discharge chamber 13 of the cavity substrate 1 is formed for each of the first nozzle holes 6 (nozzle holes 8), and has an elongated shape in the AA line direction.

  Next, the operation of the droplet discharge head 100 will be briefly described. As described above, the oscillation circuit 22 is connected to the cavity substrate 1 of the droplet discharge head 100 and each individual electrode 17. Then, a pulse voltage is applied between the cavity substrate 1 and the individual electrode 17 by the oscillation circuit 22. Then, a potential difference is generated between the cavity substrate 1 and the individual electrode 17, and an electrostatic force is generated. Therefore, the vibration plate 12 bends toward the individual electrode 17, and droplets such as ink accumulated in the reservoir 14 flow into the discharge chamber 13. Thereafter, when the pulse voltage applied between the cavity substrate 1 and the individual electrode 17 disappears, the diaphragm 12 is restored to the original state position, and the pressure inside the discharge chamber 13 is increased. A droplet is ejected.

  Next, a silicon substrate processing method for manufacturing the nozzle plate 3 will be described. 4 to 8 are longitudinal sectional views showing the manufacturing process of the nozzle plate 3. 4 to 8 show a peripheral portion of the nozzle hole 8 in a longitudinal section along the line AA shown in FIG. The manufacturing process of the nozzle plate 3 will be described with reference to FIGS. Further, in the droplet discharge head 100, it is assumed that the central axes of the first nozzle hole 6 and the second nozzle hole 7 coincide with each other with high accuracy as described above.

(A) First, for example, a silicon substrate 3a having a thickness of 280 μm is prepared, set in a thermal oxidation apparatus, and a silicon oxide film (SIO ₂ film) 50 having a thickness of 1 μm is uniformly formed on the entire surface of the silicon substrate 3a. Film. For example, the silicon oxide film 50 is formed by thermal oxidation for 4 hours in a mixed atmosphere of oxygen and water vapor at a temperature of 1075 ° C. using a thermal oxidation apparatus.

(B) Next, a resist (not shown) is coated on the bonding surface 11 of the silicon substrate 3a, and the portion 6a to be the first nozzle hole 6 and the portion 7a to be the second nozzle hole 7 are patterned, and the portion Remove the resist. The portion 6a to be the first nozzle hole 6 is patterned into a circular shape having the same diameter as the diameter of the first nozzle hole 6 formed in a cylindrical shape. As will be described in detail later, the portion 7a to be the second nozzle hole 7 is patterned into a plurality of ring shapes having different sizes. In the plurality of ring-shaped patterning, the diameter of the ring shape increases from the central axis toward the outer periphery. Moreover, the ring width between each ring shape becomes narrow as it goes to an outer periphery from a center axis line (refer FIG. 9).

Then, for example, the silicon oxide film 50 is etched with a buffered hydrofluoric acid solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed in a ratio of 1: 6 to expose the silicon substrate 3a, and the resist is removed by washing with sulfuric acid or the like. The silicon oxide film 50 subjected to this patterning functions as an etching mask. The resist-coated surface later becomes the bonding surface 11 of the nozzle plate 3. Further, the patterning of the portion 7a to be the second nozzle hole 7 is not limited to a complete ring shape. For example, it is only necessary to secure a ring width that can be converted to SiO ₂ by thermal oxidation, and patterning may be performed such that ribs are formed and the silicon substrate 3a is exposed at a predetermined interval (see FIG. 10).

(C) After patterning the portion 6a to be the first nozzle hole 6 and the portion 7a to be the second nozzle hole 7, the portion where the silicon oxide film 50 is opened by the ICP dry etching apparatus is replaced with, for example, the first nozzle hole The first nozzle hole 6 is formed by performing anisotropic dry etching vertically so that the central portion of the portion 6a to be 6 becomes a depth of 70 μm. C ₄ F ₈ and SF ₆ can be used alternately as etching gases for this anisotropic dry etching. At this time, C ₄ F ₈ is preferably used to protect the side surface so that etching does not proceed in the side direction, and SF ₆ is preferably used to promote etching in the vertical direction.

  At the same time, the opened portion of the silicon oxide film 50 is also etched by the patterning formed in the portion 7 a that becomes the second nozzle hole 7. At this time, due to the microloading effect (a phenomenon in which the etching depth becomes shallower as the opening becomes narrower), which is a phenomenon peculiar to the dry etching apparatus, the depth of the ring shape that is formed narrower toward the outer periphery is reduced. Etching is gradually performed so as to become shallower. That is, the width of the ring shape to be patterned on the portion 7a to be the second nozzle hole 7 is not particularly limited, but may be determined based on this microloading effect.

(D) The silicon oxide film 50 remaining on the surface of the silicon substrate 3a is removed with an aqueous hydrofluoric acid solution.
(E) Then, the silicon substrate 3a is set in a thermal oxidation apparatus, and a thickness of 1 μm is formed on the side and bottom surfaces of the portion 6a to be the first nozzle hole 6 and the portion 7a to be the second nozzle hole 7 in the silicon substrate 3a. A silicon oxide film 55 is uniformly formed. This silicon oxide film 55 is preferably formed by thermal oxidation for 4 hours under conditions of an oxidation temperature of 1075 ° C. and a mixed atmosphere of oxygen and water vapor using a thermal oxidation apparatus, for example. In this case, the wall is formed between the ring-shaped portion 7a of the second nozzle hole 7 is completely made to be SiO ₂ of. Generally, when an oxide film is formed on silicon by thermal oxidation, silicon having a thickness of 45% of the thickness of the oxide film changes to an oxide film.

  That is, if the width of the ring shape desired to be changed by thermal oxidation is W and the film thickness of the oxide film is T, both sides of the wall formed between the ring-shaped etched portions are formed. The relationship 2 × T × 0.45 is established. Therefore, when it is desired to increase W, the value of T may be set so that T = W / 0.9. Here, the case where the film thickness of the silicon oxide film 55 is 1 μm has been described as an example, but the present invention is not limited to this.

(F) The silicon oxide film 55 is removed again with a hydrofluoric acid aqueous solution. Then, since the wall formed between each ring shape of the portion 7a that becomes the second nozzle hole 7 is completely made of SiO ₂ , the funnel-shaped second nozzle hole 7 is formed. . That is, the first nozzle hole 6 and the second nozzle hole 7 can be formed simultaneously. Therefore, it is possible to reduce the number of steps required for manufacturing as compared with the case where the first nozzle hole 6 and the second nozzle hole 7 are individually formed.

  Further, the thickness accuracy when the silicon substrate 3a is oxidized by thermal oxidation is high including uniformity in the substrate surface, and the processing accuracy of the first nozzle hole 6 can be kept high. Furthermore, since the first nozzle hole 6 and the second nozzle hole 7 can be formed at the same time, it is possible to eliminate the deviation of the central axes of the first nozzle hole 6 and the second nozzle hole 7. That is, the center axes of the first nozzle hole 6 and the second nozzle hole 7 are made to coincide with each other with high accuracy without adjusting the alignment of the center lines of the first nozzle hole 6 and the second nozzle hole 7. It can be done. Accordingly, the ink ejection performance is further improved.

(G) The silicon substrate 3a is set in a thermal oxidation apparatus, and a silicon oxide film 56 having a thickness of 1 μm is uniformly formed on the entire surface of the silicon substrate 3a. This silicon oxide film 56 is preferably formed by thermal oxidation for 2 hours under conditions of an oxidation temperature of 1000 ° C. and an oxygen atmosphere using, for example, a thermal oxidation apparatus. Since the silicon oxide film 56 is formed by thermal oxidation, the silicon oxide film 56 is also uniformly formed on the inner walls of the portion 6a that becomes the first nozzle hole 6 and the portion 7a that becomes the second nozzle hole 7. Will be.

(H) Next, a support substrate 40 made of a transparent material such as glass is attached to the bonding surface 11 of the silicon substrate 3a (shown in the state of being inverted upside down in FIG. 6). The support substrate 40 may be attached to the silicon substrate 3a via a double-sided tape 45 provided with a self-peeling layer 41 whose adhesion is easily reduced by stimulation with ultraviolet rays or heat on one side. The support substrate 40, the double-sided tape 45, and the self-peeling layer 41 are referred to as a WSS (Wafer Support System) substrate 49.

  The surface of the self-peeling layer 41 of the WSS substrate 49 and the bonding surface 11 of the silicon substrate 3a face each other and are bonded together in a vacuum, so that the air can be bonded cleanly without leaving bubbles at the bonding interface. In this way, it is possible to prevent bubbles from remaining at the bonding interface between the self-peeling layer 41 and the silicon substrate 3a. That is, since bubbles do not remain, the surface of the ink discharge surface 10 of the silicon substrate 3a becomes smooth, and variations in the thickness of the silicon substrate 3a when thinned in the polishing process are eliminated.

(I) After the WSS substrate 49 is attached to the silicon substrate 3a, polishing is performed from the ink discharge surface 10 side of the silicon substrate 3a by a back grinder, polisher, CMP (Chemical Mechanical Polishing), etc., and the tip of the first nozzle hole 6 The silicon substrate 3a is thinned until the silicon oxide film 56 is removed. At this time, the inner walls of the first nozzle hole 6 and the second nozzle hole 7 are cleaned in a water washing removal process of the abrasive in the nozzle hole 8 or the like. Further, if the silicon substrate 3a is thinned to the vicinity of the silicon oxide film 56 at the tip of the first nozzle hole 6 with a back grinder, and the finishing of the thinning is performed by a polisher or CMP, the surface of the silicon substrate 3a is mirror-finished. Can be finished.

The removal of the silicon oxide film 56 at the tip of the first nozzle hole 6 may be performed by dry etching. For example, by dry etching using SF ₆ as an etching gas, the silicon substrate 3 a is thinned to the tip of the first nozzle hole 6, and the silicon oxide film 56 at the tip of the first nozzle hole 6 exposed on the surface is CF. _It may be removed by dry etching using ₄ or CHF ₃ as an etching gas.

(J) A silicon oxide film (SIO ₂ film) 57 is formed on the ink discharge surface 10 of the silicon substrate 3a to a thickness of 0.1 μm using a sputtering apparatus. The formation of the silicon oxide film 57 is not limited to the sputtering method using a sputtering apparatus as long as the silicon oxide film 57 can be formed at a temperature that does not deteriorate the self-peeling layer 41 (for example, about 100 ° C.). . However, in consideration of ink resistance and the like, it is necessary to form a dense silicon oxide film 57, and it is desirable to use an apparatus such as a sputtering apparatus that can form a dense film at room temperature.

(K) Subsequently, ink repellent treatment is performed on the surface of the ink ejection surface 10 of the silicon substrate 3a. In this ink repellent treatment, an ink repellent material containing F (fluorine) atoms is formed on the ink discharge surface 10 by vapor deposition, dipping, or the like to form, for example, an ink repellent layer 46 having a thickness of 0.1 μm. It is good to do it. At this time, the ink repellent layer 46 is also formed on the inner walls of the first nozzle hole 6 and the second nozzle hole 7. That is, since the ink repellent layer 46 is formed by vapor deposition or dipping, the entire inner wall of the nozzle hole 8 is simultaneously subjected to ink repellent treatment.

(L) When ink repellent treatment is applied to the entire inner wall of the nozzle hole 8, the WSS substrate 49 bonded to the silicon substrate 3a is peeled off. The WSS substrate 49 is peeled off by first attaching the dicing tape 47 as a support tape to the ink discharge surface 10. In addition, although the case where the dicing tape 47 is stuck on the ink discharge surface 10 is shown as an example, the present invention is not limited to this. For example, a mask substrate such as a silicon mask or a metal mask may be bonded and attached to the ink discharge surface 10.

(M) When the dicing tape 47 is attached to the ink ejection surface 10, UV (ultraviolet) light is irradiated from the WSS substrate 49 side to peel the WSS substrate 49 from the silicon substrate 3a. For example, the UV light irradiation may be performed by vacuum suction fixing the ink discharge surface 10 to a suction stage or the like. This UV light is irradiated to cause peeling (referred to as intra-layer peeling or interface peeling) inside the self-peeling layer 41 of the WSS substrate 49 or at the adhesive interface with the silicon substrate 3a.

  That is, when the self-peeling layer 41 receives light of a predetermined intensity (here, UV light), the bonding force between atoms or molecules of the material constituting the self-peeling layer 41 disappears or decreases, thereby ablation. (Ablation, excision or removal) is caused to facilitate separation. In such peeling, for example, when the component in the constituent material of the self-peeling layer 41 is released as a gas and results in separation (separation within the layer), the peeling layer 41 absorbs light and becomes gas, There is a case where the vapor is released to cause separation (interfacial separation).

  By doing so, the WSS substrate 49 can be easily peeled from the silicon substrate 3a. Note that the support substrate 40 constituting the WSS substrate 49 is preferably made of glass or the like that transmits light. That is, when the support substrate 40 is peeled from the silicon substrate 3a, the self-peeling layer 41 is surely provided with the peeling energy possessed by light irradiated from the back surface of the support substrate 40 (opposite surface to which the silicon substrate 3a is bonded). It is to make it reach. That is, if the support substrate 40 is made of a material that transmits light, sufficient peeling energy is given to the self-peeling layer 41.

  Moreover, the material which comprises the self peeling layer 41 should just have the above characteristics, and is not specifically limited. For example, amorphous silicon (a-Si, amorphous silicon), silicon oxide, silicate compounds, and nitride ceramics such as silicon nitride, aluminum nitride, and titanium nitride may be used as the material. Further, an organic polymer material or the like in which interatomic bonds are broken by light irradiation may be used. Furthermore, a metal such as aluminum, lithium, titanium, manganese, indium, tin, yttrium, lanthanum, cerium, neodymium, praseodymium, gadolinium, samarium, or an alloy containing at least one of these metals may be used as a material.

(N) After the WSS substrate 49 is peeled off, the excess repellent formed on the surface of the bonding surface 11 and the inner walls of the first nozzle hole 6 and the second nozzle hole 7 by performing Ar plasma treatment or O ₂ plasma treatment. The ink layer 46 is removed. In addition, since the dicing tape 47 is attached to the ink repellent layer 46 formed on the ink discharge surface 10, the ink repellent layer 46 formed on the ink discharge surface 10 is subjected to Ar plasma treatment or O ₂ plasma treatment. Even if you do it, it will be protected.

(O) Next, the dicing tape 47 attached as a support tape to the ink discharge surface 10 of the silicon substrate 3a is peeled off. The dicing tape 47 may be peeled off after the bonding surface 11 of the silicon substrate 3a is fixed by vacuum suction using the suction jig 70 or the like. Here, the case where vacuum suction is performed by the suction jig 70 is shown as an example, but the present invention is not limited to this.

(P) Finally, the suction fixing of the suction jig 70 is released, and the nozzle plate 3 is recovered from the silicon substrate 3a. The outer ring groove of each nozzle plate 3 is carved on the silicon substrate 3a. Therefore, the nozzle plate 3 is divided into individual pieces and can be collected at the stage of picking up the silicon substrate 3a from the suction jig 70. The nozzle plate 3 is produced by the above process.

  9 and 10 are top views showing a patterning example of the nozzle hole 8 as viewed from above. Based on FIGS. 9 and 10, the etching patterning shape of the portion 6a to be the first nozzle hole 6 and the portion 7a to be the second nozzle hole 7 during processing of the nozzle hole 8, which is a characteristic portion of the present invention. explain. Note that the silicon oxide film 50 is used as an etching mask when etching a portion to be the first nozzle hole 6 and a portion to be the second nozzle hole 7 (see FIG. 4B).

  9B, as described in FIG. 4B, the portion 6a to be the first nozzle hole 6 is formed in a circular pattern, and the portion 7a to be the second nozzle hole 7 has a plurality of different sizes. The pattern is formed in a ring shape. The width between the ring shapes is formed so as to gradually decrease from the center line axis toward the outer periphery. This is because the second nozzle hole 7 is formed by utilizing the microloading effect that is a phenomenon peculiar to the dry etching apparatus. For example, the width between the edge of the first nozzle hole 6 and the ring shape closest to the first nozzle hole 6 is A, and the width between the ring shape closest to the first nozzle hole 6 and the ring shape closest to the second is B. If the width of the second closest ring shape and the third closest ring shape is C, then A> B> C.

When the second nozzle hole 7 is formed by dry etching, if the microloading effect is used, the etching depth of each ring shape of the portion 7a that becomes the second nozzle hole 7 is different by one dry etching. can do. That is, the narrower the ring shape, the shallower the etching depth. The walls formed between the ring-shaped etching portion of the portion 7a of the second nozzle hole 7 is completely made to be SiO ₂ of.

  Therefore, if the formed silicon oxide film 55 is removed, the second nozzle hole 7 can be formed simultaneously with the formation of the first nozzle hole 6. Further, if the number and width of the ring shape are determined in consideration of the characteristics of the microloading effect, the funnel-shaped second nozzle hole 7 with high processing accuracy can be easily reduced while reducing the number of steps required for forming the nozzle hole 8. Can be formed. The width of each ring shape may be determined based on the above formula.

  In FIG. 10, the portion 6a that becomes the first nozzle hole 6 is formed in a circular pattern, and the rib 7 is formed in the ring shape on the portion 7a that becomes the second nozzle hole 7 so that the silicon substrate is exposed at a predetermined interval. Patterning is performed as described above. That is, it is only necessary to make the etching depth of each rib of the portion 7a to be the second nozzle hole 7 different by dry etching once using the microloading effect.

At this time, may wall formed between the etched portion of the portion 7a of the second nozzle hole 7 is to determine the number and spacing of the ribs so that there is complete SiO ₂ of. Also, if the number and width of the ribs are determined in consideration of the characteristics of the microloading effect, the funnel-shaped second nozzle hole 7 with high processing accuracy can be easily formed while reducing the number of steps required for forming the nozzle hole 8. Can be formed. The predetermined interval between the ribs may be determined based on the above formula.

  9 and 10 show an example in which the funnel-shaped second nozzle hole 7 is formed by the microloading effect, thermal oxidation, and oxide film removal. Therefore, it is sufficient that the funnel-shaped (tapered) second nozzle hole 7 can be formed by the microloading effect, thermal oxidation, and oxide film removal, and the present invention is not limited to the patterning as shown in FIGS.

Next, the manufacturing process of the droplet discharge head 100 will be described.
11 and 12 are longitudinal sectional views showing a process of manufacturing the bonded substrate 60 by bonding the cavity substrate 1 and the glass substrate 2. A manufacturing process of the bonded substrate 60 in which the cavity substrate 1 and the glass substrate 2 are bonded will be described with reference to FIGS. 11 and 12. In addition, in the manufacturing process of the joining substrate 60, the manufacturing process of the glass substrate 2 and the cavity board | substrate 1 shall be demonstrated easily. Moreover, the manufacturing method of the cavity substrate 1 and the glass substrate 2 is not limited to what is shown by FIG.10 and FIG.11.

  First, the recess 9 is formed by etching the glass substrate 2a made of borosilicate glass or the like with, for example, hydrofluoric acid using gold or chromium as an etching mask. A plurality of the recesses 9 are formed in a groove shape slightly larger than the shape of the individual electrode 17, and a plurality of the recesses 9 are formed. Then, an individual electrode 17 made of ITO is formed in the recess 9 by sputtering, for example. Thereafter, a hole serving as the ink supply port 18 is formed by a drill or the like to produce the glass substrate 2 (FIG. 11A).

  Next, for example, after both surfaces of a silicon substrate 1a having a thickness of 525 μm are mirror-polished, a silicon oxide film 23 having a thickness of 0.1 μm made of TEOS is formed on one surface of the silicon substrate 1a by plasma CVD (FIG. 11B). )). Note that a boron doped layer for etching stop may be formed before the silicon oxide film 23 is formed. By forming the diaphragm 12 from a boron-doped layer, the diaphragm 12 with high thickness accuracy can be formed.

  Then, the silicon substrate 1a shown in FIG. 11 (b) and the glass substrate 2 shown in FIG. 11 (a) are heated to, for example, 360 ° C., and the anode is connected to the silicon substrate 1a and the cathode is connected to the glass substrate 2 to 800V. A voltage of a certain level is applied to perform anodic bonding to produce a bonded substrate 60 (FIG. 11C). After the silicon substrate 1a and the glass substrate 2 are anodically bonded, the bonded substrate 60 is etched with a potassium hydroxide aqueous solution or the like, thereby thinning the entire silicon substrate 1a to a thickness of, for example, 140 μm (FIG. 11). (D)).

  Then, a TEOS film 26 having a thickness of, for example, 1.5 μm is formed on the entire upper surface of the silicon substrate 1a (the surface opposite to the surface to which the glass substrate 2 is bonded) by plasma CVD. The TEOS film 26 is patterned with a resist for forming a concave portion to be the discharge chamber 13, the reservoir 14, and the orifice 15, and the TEOS film 26 in this portion is removed by etching. Thereafter, the silicon substrate 1a is etched with a potassium hydroxide aqueous solution or the like, thereby forming recesses to become the discharge chamber 13, the reservoir 14, and the orifice 15 (FIG. 12E).

  In the wet etching step of FIG. 12 (e), for example, a 35% by weight aqueous potassium hydroxide solution can be used first, and then a 3% by weight aqueous potassium hydroxide solution can be used. By carrying out like this, the surface roughness of the diaphragm 12 can be suppressed. After the etching of the silicon substrate 1a is completed, the bonding substrate 60 is etched with a hydrofluoric acid aqueous solution to remove the TEOS film 26 formed on the silicon substrate 1a.

  Further, laser processing is performed on the hole portion that becomes the ink supply port 18 of the glass substrate 2 so that the ink supply port 18 penetrates the glass substrate 2 (FIG. 12F). Next, a droplet protective film 24 made of TEOS or the like is formed, for example, with a thickness of 0.1 μm, for example, by CVD on the surface of the silicon substrate 1a where the recesses or the like that will become the discharge chamber 13 are formed (FIG. 12G). ). Then, a portion that becomes the electrode outlet 25 is opened by RIE (Reactive Ion Etching) or the like.

  In addition, the silicon substrate 1 a is machined or laser processed to penetrate the ink supply port 18 to the portion that becomes the reservoir 14. Thereby, the bonded substrate 60 in which the cavity substrate 1 and the glass substrate 2 are bonded is completed. Then, the bonding substrate 60 is bonded to the nozzle plate 3 described above to complete the droplet discharge head 100. A sealant (not shown) may be applied to seal the space (gap 20) between the diaphragm 12 and the individual electrode 17.

  FIG. 13 is a perspective view showing an example of a droplet discharge device 150 on which the above-described droplet discharge head 100 is mounted. A droplet discharge device 150 shown in FIG. 13 represents a general inkjet printer. The droplet discharge device 150 can be manufactured by a known manufacturing method. Further, the above-described droplet discharge head 100 has a feature in the manufacturing process of the nozzle plate 3 as shown in FIGS.

  In addition to the droplet discharge device 150 shown in FIG. 13, the droplet discharge head 100 obtained in the embodiment can be used to manufacture various color filters for liquid crystal displays and organic EL display devices. The present invention can also be applied to the formation of the light-emitting portion, the discharge of a biological liquid, and the like. The droplet discharge head 100 obtained in the embodiment can also be used for a piezoelectric drive type droplet discharge device or a bubble jet (registered trademark) type droplet discharge device.

  For example, when the droplet discharge head 100 is used as a dispenser and used for discharging onto a substrate that is a microarray of biomolecules, DNA (Deoxyribo Nucleic Acids), other nucleic acids (for example, Ribo Nucleic Acid: ribonucleic acid, (Peptide Nucleic Acids: peptide nucleic acid, etc.) A liquid containing a probe such as a protein may be discharged.

  Note that the droplet discharge head, the droplet discharge device, the method for manufacturing the droplet discharge head, and the method for manufacturing the droplet discharge device according to the embodiment of the present invention are limited to the contents described in the above embodiments. It can be modified within the scope of the idea of the present invention. Moreover, although the case where the droplet discharge head 100 according to the embodiment has a three-layer structure including the glass substrate 2, the cavity substrate 1, and the nozzle plate 3 has been described as an example, the present invention is not limited to this. For example, the droplet discharge head 100 may be configured as a four-layer structure including a glass substrate, a cavity substrate, a reservoir substrate, and a nozzle plate.

It is a disassembled perspective view which shows the state which decomposed | disassembled the droplet discharge head which concerns on embodiment. It is a longitudinal cross-sectional view which shows the cross-sectional structure of a droplet discharge head. FIG. 6 is a top view of the nozzle plate as viewed from the ink ejection surface side. It is the longitudinal cross-sectional view which showed the manufacturing process of the nozzle plate. It is the longitudinal cross-sectional view which showed the manufacturing process of the nozzle plate. It is the longitudinal cross-sectional view which showed the manufacturing process of the nozzle plate. It is the longitudinal cross-sectional view which showed the manufacturing process of the nozzle plate. It is the longitudinal cross-sectional view which showed the manufacturing process of the nozzle plate. It is a top view which shows the state which looked at the patterning example of the nozzle hole from the top. It is a top view which shows the state which looked at the patterning example of the nozzle hole from the top. It is a longitudinal cross-sectional view which shows the process of manufacturing a joining board | substrate. It is a longitudinal cross-sectional view which shows the process of manufacturing a joining board | substrate. It is the perspective view which showed an example of the droplet discharge apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity substrate, 1a Silicon substrate, 2 Glass substrate, 2a Glass substrate, 3 Nozzle plate, 6 1st nozzle hole, 6a The part used as the 1st nozzle hole 6, 7 2nd nozzle hole, 7a 2nd nozzle Portion 7, 8 nozzle hole, 9 recess, 10 ink ejection surface, 11 joint surface, 12 diaphragm, 13 ejection chamber, 14 reservoir, 15 orifice, 16 insulating film, 17 individual electrode, 18 ink supply port, 19 Common electrode, 20 gap, 22 Oscillator circuit, 23 Silicon oxide film, 24 Droplet protective film, 25 Electrode outlet, 26 TEOS film, 40 Support substrate, 41 Self-peeling layer, 45 Double-sided tape, 46 Ink repellent layer, 47 Dicing Tape, 49 WSS substrate, 50 silicon oxide film, 55 silicon oxide film, 56 silicon oxide film, 57 silicon oxide film, 60 bonded substrate, 0 suction jig, 100 droplet discharge head, 150 droplet discharge device.

Claims (11)

A nozzle hole comprising a first nozzle hole and a tapered second nozzle hole which is in communication with the first nozzle hole and has a diameter gradually larger than the first nozzle hole is formed in the silicon substrate. A nozzle plate manufacturing method comprising:
The patterning of the portion serving as the second nozzle hole is performed simultaneously with the patterning of the portion serving as the first nozzle hole as a plurality of ring shapes whose diameters increase from the central axis of the second nozzle hole toward the outer periphery. A manufacturing method of a nozzle plate characterized by the above. 2. The method of manufacturing a nozzle plate according to claim 1, wherein patterning is performed so that walls are concentrically formed between the ring shapes. 3. The method of manufacturing a nozzle plate according to claim 1, wherein a rib is formed in each ring shape and patterning is performed so that the silicon substrate is exposed at a predetermined interval. The method of manufacturing a nozzle plate according to any one of claims 1 to 3, wherein a ring width between the ring shapes is gradually narrowed from the central axis toward the outer periphery. The method for manufacturing a nozzle plate according to any one of claims 1 to 4, wherein the central axis is the same as the central axis of the first nozzle hole. After dry etching the portion to be the first nozzle hole and the portion to be the second nozzle hole,
Oxidizing the surface of the silicon substrate;
6. The nozzle plate according to claim 1, wherein an oxide film formed on a side surface and a bottom surface of the portion serving as the first nozzle hole and the portion serving as the second nozzle hole is removed. Manufacturing method. The method for manufacturing a nozzle plate according to claim 6, wherein the dry etching is anisotropic dry etching by ICP discharge. Bonding a support substrate to the surface of the silicon substrate on which the second nozzle holes are formed, and thinning the opposite surface of the silicon substrate to which the support substrate is bonded;
Opening the first nozzle hole from the thinned silicon substrate side;
After performing a water repellent treatment on the surface of the silicon substrate,
The said support substrate is peeled from the said silicon substrate. The manufacturing method of the nozzle plate in any one of Claims 1-7 characterized by the above-mentioned. The method for manufacturing a nozzle plate according to claim 8, wherein the silicon substrate and the support substrate are bonded together in a vacuum. In the nozzle plate according to any one of claims 1 to 9,
A silicon substrate on which a liquid flow path including a plurality of discharge chambers for forming and vibrating droplets by forming a diaphragm on the bottom wall is formed, and individual electrodes for driving the diaphragm while facing the diaphragm with a gap A method of manufacturing a droplet discharge head, comprising: bonding a bonding substrate formed with a glass substrate on which the liquid crystal is formed. A method for manufacturing a droplet discharge device, wherein the method for manufacturing a droplet discharge head according to claim 10 is applied to manufacture a droplet discharge device.

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