JP2007098888A - Nozzle substrate manufacturing method, droplet discharge head manufacturing method, and droplet discharge apparatus manufacturing method - Google Patents

Abstract

A silicon substrate in which a nozzle shape is processed is bonded to a support substrate with a resin, and when a bonding resin filled in the nozzle is pulled out, a silicon oxide film burr and a resin residue are not left in the nozzle. A method for manufacturing a nozzle substrate, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device are provided.
A nozzle substrate manufacturing method for forming a nozzle including a first nozzle hole and a second nozzle hole in a silicon substrate, wherein the first nozzle hole and the second nozzle hole are formed. A step of bonding a support substrate to a silicon substrate using a resin and filling the resin into the recess, a step of thinning the silicon substrate, and opening a first nozzle hole from the thinned silicon substrate; , Removing the resin filled in the first nozzle hole, forming an oxide film and a water repellent film on the silicon substrate, and peeling the support substrate from the silicon substrate.
[Selection] Figure 8

Description

  The present invention relates to a method of manufacturing a nozzle substrate 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 more particularly to a nozzle substrate having high ink droplet discharge performance. The present invention relates to a manufacturing method, a manufacturing method of a droplet discharge head, and a manufacturing method of a droplet discharge device.

  In recent years, inkjet recording apparatuses have many advantages such as extremely low noise during recording, high-speed printing, and the ability to use inexpensive plain paper with high ink freedom. The so-called ink-on-demand type ink jet recording apparatus that ejects ink droplets only when recording is necessary has now become mainstream. This ink-on-demand ink jet recording apparatus does not require the collection of ink droplets unnecessary for recording.

  The ink-on-demand type ink jet head recording apparatus ejects ink droplets using an electrostatic force as a driving means, a piezoelectric vibrator, or a heating element. is there. Among them, an inkjet head recording apparatus that discharges ink droplets using electrostatic force as a driving means is particularly excellent in that the chip size can be reduced and the density can be increased, the printing performance can be improved, and the life can be extended. ing.

  An ink jet head mounted in an ink jet head recording apparatus that discharges ink droplets using electrostatic force as a driving means is configured to eject ink droplets from the tip of an ink nozzle. Therefore, it is desirable to adjust the flow path resistance of the ink droplets at the nozzle holes provided in the nozzle plate and adjust the thickness of the nozzle plate so that the optimum nozzle length is obtained.

  As such, for example, in the “nozzle forming method of an injection device for etching a silicon single crystal substrate to form a nozzle, a resist film is formed on the surface of the silicon single crystal substrate, and the rear end of the nozzle A first opening pattern is formed by removing the resist film corresponding to the side, and a second opening pattern smaller than the first opening pattern is formed by removing the resist film corresponding to the tip side of the nozzle. An opening 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, from the rear end side toward the front end side. A nozzle forming method of an injection device characterized by forming a nozzle having a small cross section in a staircase shape has been proposed (for example, Patent Literature Reference).

  The nozzle forming method of this spraying apparatus is a method in which first and second nozzle holes having different inner diameters are formed in two stages by anisotropic dry etching using ICP (Inductively Coupled Plasma) discharge from the bonding surface side of the silicon single crystal substrate. In this method, a part of the discharge surface opposite to the bonding surface is dug down by anisotropic wet etching to adjust the nozzle length.

  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. The other surface is subjected to isotropic etching having a certain degree of anisotropy to form an ink inlet hole, and after removing the etching mask, a thermal oxide film is formed. ” A nozzle plate and a manufacturing method thereof have been proposed (see, for example, Patent Document 2).

  This inkjet head nozzle plate and its manufacturing method employ a method in which a silicon substrate is polished in advance to a desired thickness and then subjected to dry etching on both sides of the silicon substrate to form nozzle holes. That is, the first nozzle hole (nozzle) is formed on one surface of the silicon substrate using anisotropic dry etching, and the second nozzle hole is formed on the other surface using isotropic dry etching (plasma etching). (Ink entrance hole) is formed.

Japanese Patent Application Laid-Open No. 11-28820 (pages 4, 5 and 3, 4) Japanese Patent Laid-Open No. 9-57981 (page 2, FIG. 1)

  In the nozzle forming method of the injection device described in Patent Document 1, the tip opening of the nozzle is opened on the bottom surface of the recess formed on the opposite surface of the nozzle plate. As described above, if the discharge surface on which the nozzle is open is on a surface that is deeply lowered by one step from the nozzle plate, there is a possibility that the ink droplet may be bent or the nozzle may be clogged. That is, there is a problem that wiping work for wiping paper dust, ink or the like adhering to the ejection surface of the nozzle with a rubber piece or a felt piece becomes difficult.

  Moreover, in the nozzle plate for inkjet heads described in Patent Document 2 and the manufacturing method thereof, the thickness of the silicon substrate has to be further reduced as the density of the inkjet heads increases. Such a silicon substrate has a problem that it is easily broken during the manufacturing process and is expensive. Furthermore, during dry etching processing, cooling is performed from the back surface of the substrate with He (helium) gas or the like so as to stabilize the processing shape, but the He gas leaks when the nozzle hole penetrates and etching becomes impossible. There was a case.

Therefore, a method is conceivable in which a nozzle shape is formed in advance on a silicon substrate and bonded to a support substrate and then subjected to thinning (grinding or etching) to open the nozzle. In order to prevent the tip of the nozzle from being chipped when the nozzle is opened, a method of filling the bonding resin into the nozzle in advance when bonding the support substrate is conceivable. However, when the nozzle is opened and a silicon oxide film (SIO ₂ film) and a water repellent film are formed on the nozzle surface, the bonding resin filled in the nozzle is pulled out, and the silicon oxide film is formed on the nozzle tip ridge. There was a problem that burrs and resin residues remained. When such a nozzle plate is used, the ink droplet ejection performance is degraded.

  In the present invention, when a silicon substrate having a nozzle shape processed is bonded to a support substrate with a resin, and a bonding resin filled in the nozzle is pulled out, no burrs or resin residues of the silicon oxide film remain in the nozzle. It is an object of the present invention to provide a method for manufacturing a nozzle substrate, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device.

  The method for manufacturing a nozzle substrate according to the present invention includes a nozzle comprising a silicon substrate, a first nozzle hole, and a second nozzle hole communicating with the first nozzle hole and having a diameter larger than that of the first nozzle hole. A method of manufacturing a nozzle substrate for forming a concave portion, wherein a first nozzle hole and a second nozzle hole are formed by dry etching, and a second nozzle hole of a silicon substrate is formed using a resin. And a step of filling the inside of the recess with the support substrate and bonding the resin to the inner surface, and thinning a surface opposite to the surface of the silicon substrate to which the support substrate is bonded. A step of opening a nozzle hole, a step of removing the resin filled in the recess from a portion where the first nozzle hole is opened, and a step of forming an oxide film and a water repellent film on the thinned surface of the silicon substrate And support substrate Characterized by a step of peeling from down the substrate.

  In the stage before forming the oxide film on the thinned surface of the silicon substrate, the resin in the recess that becomes the nozzle is removed, so that the first nozzle hole serves as a ridge, and the inner wall of the recess that becomes the nozzle An oxide film is not formed on the tangent to the surface of the resin filled in the recess. That is, when the resin is pulled out, the oxide film does not remain as burrs in the opening portion of the first nozzle hole of the silicon substrate. Furthermore, since the oxide film does not remain as burrs, resin residues can be eliminated inside the recesses.

  The nozzle substrate manufacturing method according to the present invention is characterized in that the silicon substrate and the support substrate are bonded together in a vacuum. That is, by performing the process of bonding the support substrate to the silicon substrate in a vacuum, it is possible to fill the recesses that become the nozzles with resin without the accumulation of bubbles or the like in the recesses that become the nozzles. Therefore, it is possible to eliminate the unevenness of the resin filled in the recess that becomes the nozzle.

  In the method for manufacturing a nozzle substrate according to the present invention, a support substrate is bonded to a surface of a silicon substrate where a recess is formed using a resin, and the resin is coated on the support substrate in the step of filling the resin into the recess. Then, the silicon substrate and the support substrate are bonded together, and the resin is filled in the recess. By coating the resin on the support substrate side, it is possible to fill the resin into the concave portion serving as the nozzle without causing bubbles or the like to accumulate in the concave portion serving as the nozzle.

  The method for manufacturing a nozzle substrate according to the present invention is characterized in that a release layer that is separated by light is formed between a silicon substrate and a support substrate. In this way, a release layer that is separated by light is formed between the silicon substrate and the support base, and the silicon substrate and the support substrate are bonded together. For example, light such as laser or ultraviolet light is irradiated. Thus, the support substrate can be easily peeled off.

  The nozzle substrate manufacturing method according to the present invention is characterized in that the support substrate is made of a transparent material. If the support substrate is made of a transparent material such as glass, light such as laser or ultraviolet light can easily reach the release layer. Accordingly, the amount of light necessary for the separation layer to be separated can sufficiently reach the separation layer, and the support substrate can be easily separated from the silicon substrate.

  In the method of manufacturing a nozzle substrate according to the present invention, in the step of thinning the surface opposite to the surface where the support substrate of the silicon substrate is bonded, the silicon substrate is formed by any one of back grinder, polisher, CMP, or a combination thereof. Is characterized by polishing. As described above, since the silicon substrate is thinned by the back grinder, the polisher, and the CMP, the surface of the silicon substrate can be finished finely.

In the method of manufacturing a nozzle substrate according to the present invention, in the step of removing the resin filled in the recess from the portion where the first nozzle hole is opened, the resin filled in the recess is removed by O ₂ plasma treatment. It is characterized by. Since the resin filled in the concave portion serving as the nozzle is removed by the O ₂ plasma treatment, the resin can be easily removed. Further, if the resin filled in the concave portion serving as a nozzle is removed by O ₂ plasma treatment, the resin can be removed cleanly.

  The method for manufacturing a nozzle substrate according to the present invention includes the step of removing the resin filled in the recesses from the portion where the first nozzle hole is opened, and the entire resin filled in the first nozzle hole, Part or all of the resin filled in the two nozzle holes is removed. If a part or all of the resin filled in the recesses (first nozzle hole, second nozzle hole) serving as nozzles is removed, an oxide film is formed at the opening of the first nozzle hole of the silicon substrate. There is no remaining. Therefore, the oxide film does not remain as burrs in the opening portion of the first nozzle hole of the silicon substrate.

The nozzle substrate manufacturing method according to the present invention is characterized in that the first nozzle hole and the second nozzle hole are formed by dry etching using C ₄ F ₈ and SF ₆ . A step of forming a recess (first nozzle hole and second nozzle hole) to be a nozzle is performed by anisotropic dry etching using C ₄ F ₈ and SF ₆ to manufacture a highly accurate nozzle. be able to. Therefore, it is possible to manufacture a nozzle substrate with a high yield.

  The method for manufacturing a nozzle substrate according to the present invention is characterized in that after the support substrate is peeled off from the silicon substrate, the resin is peeled off from the silicon substrate. If the resin is peeled off from the silicon substrate after the step of peeling the support substrate from the silicon substrate, the resin inside the recess that becomes the nozzle is also pulled out together with the resin layer, so the filler inside the recess that becomes the nozzle A process such as removal is unnecessary. Therefore, the productivity of the nozzle substrate is improved.

  In the method of manufacturing the nozzle substrate according to the present invention, in the step of peeling the support substrate from the silicon substrate, a member for protecting the water repellent film is attached to the thinned surface of the silicon substrate, and then the support substrate is attached to the silicon substrate. It is characterized by peeling from. As described above, the member for protecting the water repellent film is attached to the thinned surface of the silicon substrate, and then the support substrate is peeled off from the silicon substrate. Therefore, when the resin is peeled off from the concave portion serving as the nozzle, The water film is not peeled off together. That is, since the oxide film formed on the lower surface of the water repellent film is also protected, the oxide film does not remain as burrs in the opening portion of the first nozzle hole of the silicon substrate.

  The method for producing a nozzle substrate according to the present invention is characterized in that the member for protecting the water-repellent film is a tape. The nozzle substrate manufacturing method according to the present invention is characterized in that the member for protecting the water repellent film is a mask. As described above, since the water-repellent film is protected with the tape or the mask, it is possible to reduce labor and cost for manufacturing without preparing or preparing a new member.

  The method for manufacturing a nozzle substrate according to the present invention is characterized in that after the support substrate is peeled off from the silicon substrate, the inside of the recess is plasma-treated from the surface opposite to the thinned surface of silicon. Even if the inside of the recess that becomes the nozzle is plasma-treated, the water-repellent film formed on the surface of the silicon substrate is protected with a tape or mask, so that the water-repellent film on the surface of the silicon substrate can be plasma-treated. Absent. Accordingly, the water repellency of the nozzle substrate is not lowered.

  A manufacturing method of a droplet discharge head according to the present invention is characterized in that a droplet discharge head is manufactured by using the above-described nozzle substrate manufacturing method. Therefore, it is possible to manufacture a droplet discharge head having the above effects and high ink droplet discharge performance. Further, since it is possible to manufacture a highly accurate nozzle substrate, the yield for manufacturing the droplet discharge head is also improved.

  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. In addition, since it is possible to manufacture a highly accurate nozzle substrate, the yield for manufacturing the droplet discharge device is also improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view showing a sectional configuration of a droplet discharge head 100 according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of the droplet discharge head 100. In FIG. 1, the drive circuit 21 is schematically shown. Further, as an example of the droplet discharge head 100 according to the first embodiment, a face ejection type droplet discharge head is shown by an electrostatic drive method. The configuration and operation of the droplet discharge head 100 will be described with reference to FIGS.

  The droplet discharge head 100 is mainly configured by bonding a cavity substrate 1, an electrode substrate 2, and a nozzle substrate 3. That is, the cavity substrate 1 is configured so that the electrode substrate 2 and the nozzle substrate 3 are sandwiched from above and below. The nozzle substrate 3 is formed of, for example, a cylindrical first nozzle hole 6 and a cylindrical second nozzle hole 7 that communicates with the first nozzle hole 6 and has a diameter larger than that of the first nozzle hole 6. Nozzle 8 is formed. 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 is bonded with the cavity substrate 1. It is formed so as to open on the surface 11. The nozzle substrate 3 is preferably made of single crystal silicon so that predetermined processing described later can be easily performed.

  The cavity substrate 1 is made of, for example, single crystal silicon, and a plurality of recesses serving as discharge chambers 13 whose bottom walls are diaphragms 12 are formed. The plurality of discharge chambers 13 are formed side by side in parallel from the front side to the back side in FIG. Further, the cavity substrate 1 has a recess serving as a reservoir 14 for supplying a droplet of ink or the like to each discharge chamber 13, and a recess serving as a narrow groove-like orifice 15 that communicates the reservoir 14 with each discharge chamber 13. Is formed.

  In this 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 bonding surface 11 of the nozzle substrate 3. Further, an insulating film (silicon oxide film) 16 made of silicon oxide or the like is formed on the entire surface of the cavity substrate 1 by, for example, CVD (Chemical Vapor Deposition) or thermal oxidation. This insulating film 16 prevents dielectric breakdown or short-circuit when the droplet discharge head 100 is driven, and also prevents the cavity substrate 1 from being etched by droplets inside the discharge chamber 13 or the reservoir 14. It is.

  An electrode substrate 2 made of, for example, borosilicate glass is bonded to the cavity substrate 2 on the diaphragm 12 side. A plurality of individual electrodes 17 facing the diaphragm 12 are formed on the electrode substrate 2. The individual electrode 17 is formed, for example, by sputtering ITO (Indium Tin Oxide). In addition, an ink supply hole 18 communicating with the reservoir 14 is formed in the electrode substrate 2. The ink supply hole 18 is connected to a hole provided in the bottom wall of the reservoir 14 and is provided to supply droplets such as ink to the reservoir 14 from the outside. When the cavity substrate 1 is made of single crystal silicon and the electrode substrate 2 is made of borosilicate glass, the cavity substrate 1 and the electrode substrate 2 can be joined by anodic bonding. A substrate obtained by bonding the cavity substrate 1 and the electrode substrate 2 is referred to as a bonded substrate 60 (described in detail later).

  Here, the operation of the droplet discharge head 100 will be described. A drive circuit 21 is connected to the cavity substrate 1 and each individual electrode 17. When a pulse voltage is applied between the cavity substrate 1 and the individual electrode 17 by the drive circuit 21, the diaphragm 12 is bent toward the individual electrode 17, and droplets of ink or the like accumulated in the reservoir 14 are ejected. It flows into the chamber 13. When the voltage applied between the cavity substrate 1 and the individual electrode 17 disappears, the diaphragm 12 returns to the original position, the pressure inside the discharge chamber 13 increases, and the liquid such as ink from the nozzle 8 is increased. Drops are ejected. In the first embodiment, an electrostatic drive type droplet discharge head is shown as an example of the droplet discharge head 100, but the present invention is not limited to this. For example, the present invention can also be applied to a droplet discharge head such as a piezoelectric drive method or a bubble jet (registered trademark) method.

  FIG. 3 is a top view of the nozzle substrate 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 substrate 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 individual first nozzle hole 6 (nozzle 8), and has an elongated shape in the AA line direction.

  In the first embodiment, a silicon substrate processing method for mainly manufacturing the nozzle substrate 3 will be described below. In the droplet discharge head 100 according to Embodiment 1, 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. By doing so, it is possible to improve the straightness of the droplets when ejecting droplets such as ink from the nozzles 8.

  4 to 11 are longitudinal sectional views showing manufacturing steps when manufacturing the droplet discharge head 100 using the silicon substrate processing method according to the first embodiment. 4 to 9 mainly show the manufacturing process of the nozzle substrate 3. 10 and 11 show the manufacturing process of the bonded substrate 60 in which the cavity substrate 1 and the electrode substrate 2 are bonded. 4 to 9 show the peripheral portion of the nozzle 8 in a longitudinal section along the line AA shown in FIG. First, a manufacturing process for producing the nozzle substrate 3 from the silicon substrate 3a will be described with reference to FIGS. Then, based on FIGS. 10 and 11, the cavity substrate 1 and the electrode substrate 2 are bonded to manufacture the bonded substrate 60, and the nozzle substrate 3 is bonded to the bonded substrate 60 to manufacture the droplet discharge head 100. The process will be described.

  First, for example, a silicon substrate 3a having a thickness of 525 μm is prepared, and a silicon oxide film 50 is uniformly formed on the entire surface of the silicon substrate 3a (FIG. 4A). 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. Next, a resist 51 is coated on one surface of the silicon substrate 3a, and the concave portion 7a to be the second nozzle hole 7 is patterned to remove the resist 51 in the concave portion 7a to be the second nozzle hole 7 (FIG. 4). (B)). The surface coated with the resist 51 will later become the bonding surface 11 of the nozzle substrate 3.

  Then, for example, the silicon oxide film 50 is half-etched with a buffered hydrofluoric acid aqueous solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed 1: 6, so that the silicon oxide film 50 in the recess 7a to be the second nozzle hole 7 is thinned. (FIG. 4C). At this time, the silicon oxide film 50 on the surface where the resist 51 is not formed is similarly thinned. Then, the resist 51 formed on one surface of the silicon oxide film 50 is removed (FIG. 4D).

  After that, the resist 51a is coated again on the surface to be the bonding surface 11, and the concave portion 6a to be the first nozzle hole 6 is patterned to remove the resist 51a in the concave portion 6a to be the first nozzle hole 6 (FIG. 4 (E)). Then, for example, the silicon oxide film 50 is half-etched with a buffered hydrofluoric acid aqueous solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed in a ratio of 1: 6 to remove the silicon oxide film 50 in the recess 6 a that becomes the first nozzle hole 6. (FIG. 5F). At this time, all the silicon oxide film 50 on the surface where the resist 51a is not formed is also removed. Then, the resist 51a remaining on the bonding surface 11 is peeled off (FIG. 5G).

Next, anisotropic etching is performed from the concave portion 6a to be the first nozzle hole 6 by dry etching by ICP (Inductively Coupled Plasma) discharge to form a concave portion 6b to be the first nozzle hole 6 having a depth of 25 μm, for example. (FIG. 5 (H)). The recess 6b that becomes the first nozzle hole 6 is a source of the recess 6c that becomes the first nozzle hole 6 (see FIG. 5J). 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 used to protect the side surface of the recess 6 b so that the etching does not proceed in the side direction of the recess 6 b, and SF ₆ is used to promote the etching of the recess 6 b in the vertical direction.

  After that, the silicon oxide film 50 is half-etched to remove the silicon oxide film 50 in the recess 7a that becomes the second nozzle hole 7 (FIG. 5I). At this time, other portions of the silicon oxide film 50 are also thinned. Then, anisotropic dry etching is performed again from the concave portion 7a (including the concave portion 6b to be the first nozzle hole 6) to be the second nozzle hole 7 by dry etching by ICP discharge, for example, a second layer having a depth of 40 μm. A recess 7b to be the nozzle hole 7 is formed (FIG. 6J). The concave portion 6b serving as the first nozzle hole is also etched simultaneously to form a concave portion 6c serving as the first nozzle hole.

  Then, after removing all the silicon oxide film 50 remaining on the silicon substrate 3a using, for example, a hydrofluoric acid aqueous solution, a silicon oxide film 50a having a thickness of 0.1 μm is uniformly formed on the entire surface of the silicon substrate 3a (see FIG. FIG. 6 (K)). This silicon oxide film 50a is formed, for example, by performing thermal oxidation for 2 hours in an oxygen atmosphere at a temperature of 1000 ° C. using a thermal oxidation apparatus. In FIG. 6K, since the silicon oxide film 50a is formed by thermal oxidation, the silicon oxide film 50a is uniformly formed on the inner walls of the recess 6c serving as the first nozzle hole and the recess 7b serving as the first nozzle hole. Is deposited.

  Next, a release layer 41 is spin-coated on one surface of a support substrate 40 made of a transparent material such as glass, and a resin layer 42 made of resin is spin-coated thereon. Then, the resin layer 42 is cured by facing the surface on which the release layer 41 and the resin layer 42 are spin-coated and the surface on which the concave portion 7b serving as the second nozzle hole of the silicon substrate 3a is formed. The substrate 40 and the silicon substrate 3a are bonded together (FIG. 6L). In the steps after FIG. 6L, the orientation of the silicon substrate 3a is upside down from that in FIGS. 4A to 6K.

  In the first embodiment, the support substrate 40 and the silicon substrate 3a in FIG. 6L are bonded together in a vacuum, and the resin constituting the resin layer 42 is formed with the recesses 6c and the second nozzles serving as the first nozzle holes. It fills with the recessed part 7b used as a nozzle hole. In this way, by bonding the support substrate 40 and the silicon substrate 3a in a vacuum, bubbles and the like are prevented from accumulating in the concave portion 6c serving as the first nozzle hole and the concave portion 7b serving as the second nozzle hole. It can be done. Note that the peeling layer 41 and the resin layer 42 in the step of FIG.

  After the silicon substrate 3a and the support substrate 40 are bonded, the first surface of the silicon substrate 3a is polished by a back grinder, polisher, CMP (Chemical Mechanical Polishing), or the like from the surface opposite to the surface where the support substrate 40 is bonded. The silicon substrate 3a is thinned until the silicon oxide film 50a at the tip of the recess 6c serving as a nozzle hole is removed (FIG. 6M). At this time, if the silicon substrate 3a is thinned to the vicinity of the silicon oxide film 50a at the tip of the recess 6c to be the first nozzle hole by the back grinder, and the finishing of the thinning is performed by a polisher or CMP, the silicon substrate 3a The surface of the mirror can be finished in a mirror shape.

Next, the silicon substrate 3a is set in a dry etching apparatus, and the resin layer 42 at the tip of the nozzle 8 (within the recess 6c serving as the first nozzle hole) is removed by O ₂ plasma treatment (FIG. 7N). This plasma treatment is performed until reaching the concave portion 7 b that becomes the second nozzle hole 7. Then, a silicon oxide film 50b is formed with a thickness of, for example, 0.1 μm on the ink discharge surface 10 of the silicon substrate 3a by a sputtering apparatus (FIG. 7 (O)).

  The silicon oxide film 50b may be formed at a temperature at which the resin layer 42 does not deteriorate (for example, about 200 ° C.) or less, and is not limited to the sputtering method. However, in consideration of ink resistance and the like, it is necessary to form a dense film, and it is desirable to use an apparatus capable of forming a dense film at room temperature, such as an ECR (Electron Cyclotron Resonance) sputtering apparatus. At this time, the silicon oxide film 50b is also formed on the inner wall of the first nozzle portion 6 and the surface of the resin (resin layer 42). However, the first nozzle hole 6 becomes like an eave, and the silicon oxide film 50b is not formed on the tangent portion between the nozzle inner wall and the resin surface.

  After the silicon oxide film 50b is formed, an ink repellent process is performed on the surface of the ink ejection surface 10 of the silicon substrate 3a (FIG. 7 (P)). This ink repellent treatment is to form an ink repellent material containing F (fluorine) atoms by vapor deposition, dipping, or the like to form a water repellent film 34 having a thickness of 0.1 μm, for example. At this time, the water repellent film 34 is also formed on the inner wall of the first nozzle hole 6. That is, since the water repellent film 34 is formed by vapor deposition or dipping of an ink repellent material, it is formed on the entire inner wall of the nozzle even if the first nozzle hole 6 has a ridge shape. .

  Then, a tape 35 (dicing tape or the like) is attached to the ink discharge surface 10 on which the water repellent film 34 is formed, and the support substrate 40 is peeled off (FIG. 8 (Q)). That is, after affixing the tape 35 to the ink discharge surface 10, the ink discharge surface 10 is vacuum-fixed and fixed to a suction stage or the like, and the support substrate 40 is peeled from the release layer 41 by irradiating a laser from the support substrate 40 side. To do. In addition, although the case where the tape 35 of the ink discharge surface 10 is affixed is shown as an example, the present invention is not limited to this. For example, a substrate such as a mask may be bonded.

  Then, the resin layer 42 is slowly peeled off from the outer peripheral portion (FIG. 8R). At this time, since the silicon oxide film 50b formed on the inner wall of the first nozzle hole 6 is protected by the water repellent film 34, the silicon oxide film is not formed on the ink discharge surface 10 even if the resin layer 42 is pulled out. No burr of 50b remains. Conventionally, since the resin layer was pulled out without sticking a tape or the like on the ink ejection surface, the silicon oxide film could not be removed cleanly. That is, the silicon oxide film remains as burrs in the nozzle opening, and the burrs remain, so that the resin layer residue also remains in the nozzle.

However, here, in order to pull out the resin layer 42 after the tape 35 or the like is attached and the water-repellent film 34 is fixed, the resin layer 42 is left without leaving burrs of the silicon oxide film 50b on the ink discharge surface 10. Can be completely pulled out. Further, since the area where the inner wall of the second nozzle hole 7 is in contact with the resin layer 42 is reduced, the resin layer 42 is further easily pulled out. This is because the resin layer 42 inside the first nozzle hole 6 is removed in advance by O ₂ plasma treatment before the tape 35 is attached.

After withdrawal of the resin layer 42, to set the silicon substrate 3a in a dry etching apparatus, attached by 0 ₂ plasma treatment or Ar plasma treatment on the inner wall of the first nozzle hole 6 and the second nozzle hole 7 water repellent The film 34 is removed (FIG. 9S). Also at this time, the water repellent film 34 formed on the ink discharge surface 10 is protected by the tape 35. Then, the nozzle substrate 3 is completed by vacuum bonding and fixing the bonding surface 11 side of the silicon substrate 3a and peeling the tape 35 (FIG. 9 (T)).

  Then, an adhesive layer is formed by transferring an adhesive or the like to the surface of the silicon substrate 3a (nozzle substrate 3) where the second nozzle holes 7 are formed, and the cavity substrate 1 (bonded) to which the electrode substrate 2 is bonded. The substrate 60) and the silicon substrate 3a are joined. Finally, for example, the bonded substrate bonded to the cavity substrate 1, the electrode substrate 2, and the nozzle substrate 3 is separated by dicing (cutting), and the droplet discharge head 100 is completed.

  Here, the peeling layer 41 and the resin layer 42 which are characteristic portions of the first embodiment will be described with reference to the process of FIG. The release layer 41 is for peeling the support substrate 40 from the silicon substrate 3a in the step of FIG. The peeling layer 41 causes peeling (referred to as in-layer peeling or interface peeling) at the inside of the peeling layer 41 or at the interface with the silicon substrate 3a when light such as a laser beam is applied (see FIG. 8Q). ).

  That is, the release layer 41 receives a light having a predetermined intensity, thereby causing ablation (ablation, excision or removal) due to disappearance or reduction of the bonding force between atoms or molecules of the material constituting the release layer 41. It is for facilitating peeling. For example, when the release layer 41 receives light of a certain intensity, the components in the constituent material of the release layer 41 are released as gas and separated, and when the release layer 41 absorbs light and becomes gas. In some cases, the vapor is released to cause separation.

  Thereby, the support substrate 40 can be easily detached from the silicon substrate 3a (nozzle substrate 3) thinned in the process of FIG. The support substrate 40 is preferably made of glass that transmits light. That is, when the support substrate 40 is peeled from the silicon substrate 3a, the peel energy possessed by the light irradiated from the back surface of the support substrate 40 (the surface opposite to the surface to which the silicon substrate 3a is bonded) reliably reaches the release layer 41. This is to make it happen. That is, if the support substrate 41 is made of a material that transmits light, sufficient peeling energy is given to the peeling layer 41.

  The material which comprises the peeling layer 41 should just have the above functions, 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.

  Among these materials, it is particularly preferable to use amorphous silicon as a constituent material of the release layer 41. Further, it is more preferable that hydrogen is contained in the amorphous silicon. This is because when the release layer 41 receives light, hydrogen is released and an internal pressure is generated in the release layer 41, which can promote the release. In this case, the hydrogen content of the release layer 41 is preferably 2% by weight or more, and more preferably 2 to 20% by weight. In addition, the hydrogen content of the release layer 41 is determined based on the film formation conditions of the release layer 41, for example, when the CVD method is used, its gas composition, gas pressure, gas atmosphere, gas flow rate, gas temperature, substrate temperature, and input. It can be adjusted by appropriately setting various conditions such as power.

  On the other hand, the resin layer 42 is for absorbing irregularities of the silicon substrate 3a and bonding the silicon substrate 3a and the support substrate 40 together. The material constituting the resin layer 42 is not particularly limited as long as it has a function of bonding the silicon substrate 3a and the support substrate 40 together. For example, a curable adhesive such as a thermosetting adhesive or a photocurable adhesive can be used as the resin layer 42.

  The resin layer 42 is preferably made mainly of a material having high dry etching resistance. This is because when the silicon substrate 3 a is etched to form the nozzle 8, the resin layer 42 can be used as an etching stop layer, and the silicon substrate 3 a can be completely penetrated. In addition, the resin layer 42 also has a function of relieving stress caused by the difference between the linear expansion coefficient of the silicon substrate 3 a and the linear expansion coefficient of the support substrate 40 during processing.

  In the first embodiment, the case where the release layer 41 and the resin layer 42 are formed as separate layers is shown as an example, but the present invention is not limited to this. For example, these layers may be composed of one layer. In this case, it can be realized by using a material having a function of bonding the silicon substrate 3a and the support substrate 40 and having a function of causing peeling by light energy or heat energy.

  Finally, a manufacturing process of the bonded substrate 60 in which the cavity substrate 1 and the electrode substrate 2 are bonded will be described with reference to FIGS. 10 and 11 are vertical cross-sectional views showing the manufacturing process of the bonded substrate 60 in which the cavity substrate 1 and the electrode substrate 2 are bonded. Note that the manufacturing process of the electrode substrate 2 and the cavity substrate 1 in the manufacturing process of the bonding substrate 60 will be briefly described. Moreover, the manufacturing method of the cavity substrate 1 and the electrode substrate 2 is not limited to that shown in FIGS.

  First, the recess 19 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 19 are formed in a groove shape that is slightly larger than the shape of the individual electrode 17. Then, an individual electrode 17 made of ITO (Indium Tin Oxide) is formed in the recess 19 by, for example, sputtering. Thereafter, a hole 18a to be the ink supply hole 18 is formed by a drill or the like to produce the electrode substrate 2 (FIG. 10A).

  Next, for example, after both surfaces of a silicon substrate 1a having a thickness of 525 μm are mirror-polished, a silicon oxide film 22 having a thickness of 0.1 μm made of TEOS (Tetra Ethyl Orthosilicate) is formed on one surface of the silicon substrate 1a by plasma CVD (Chemical Vapor Deposition). Is formed (FIG. 10B). Note that a boron doped layer for etching stop may be formed before the silicon oxide film 22 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. 10 (b) and the electrode substrate 2 shown in FIG. 10 (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 electrode substrate 2. A certain level of voltage is applied to perform anodic bonding (FIG. 10C). After the silicon substrate 1a and the electrode substrate 2 are anodically bonded, the bonded substrate 60a is etched with an aqueous potassium hydroxide solution or the like, thereby thinning the entire silicon substrate 1a to a thickness of, for example, 140 μm (FIG. 10). (D)).

  Then, a TEOS film 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 electrode substrate 2 is bonded) by plasma CVD. Then, a resist for forming a recess 13a to be the discharge chamber 13, a recess 14a to be the reservoir 14, and a recess 15a to be the orifice 15 is patterned on the TEOS film, and the TEOS film in this portion is removed by etching.

  Thereafter, the silicon substrate 1a is etched with a potassium hydroxide aqueous solution or the like to form a recess 13a that becomes the discharge chamber 13, a recess 14a that becomes the reservoir 14, and a recess 15a that becomes the orifice (FIG. 11E). At this time, the part which becomes the electrode extraction part 23 is also etched and thinned. In the wet etching step of FIG. 11 (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 60a is etched with a hydrofluoric acid aqueous solution to remove the TEOS film formed on the silicon substrate 1a. Further, laser processing is performed on the hole 18a which becomes the ink supply hole 18 of the electrode substrate 2 so that the ink supply hole 18 penetrates the electrode substrate 2 (FIG. 11 (f)). 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 13a to be the discharge chambers 13 are formed (FIG. 11G). )).

  Then, the electrode take-out part 23 is opened by RIE (Reactive Ion Etching) or the like. Further, the silicon substrate 1 a is machined or laser processed to penetrate the ink supply hole 18 to the concave portion 14 a serving as the reservoir 14. Thereby, the bonded substrate 60 in which the cavity substrate 1 and the electrode substrate 2 are bonded is completed. The bonded substrate 60 is bonded to the nozzle substrate 3. Note that a sealing agent (not shown) for sealing the space between the diaphragm 12 and the individual electrode 17 may be applied to the electrode extraction portion 23.

  In the ink discharge apparatus 100 according to the first embodiment, the resin layer 42 remaining in the first nozzle hole 6 is formed to reach the second nozzle hole 7 before the silicon oxide film 50b is formed on the ink discharge surface 10. Try to remove. Therefore, the first nozzle hole 6 plays a role like a ridge, and the silicon oxide film 50b is not formed at the tangent portion between the nozzle inner wall and the surface of the resin (resin layer 42).

  That is, when the resin layer 42 is pulled out, the silicon oxide film 50b does not remain as burrs in the opening portion of the first nozzle hole 6, and the residue of the resin layer 42 is also eliminated inside the first nozzle hole 6. be able to. In addition, the support substrate 40 is peeled off by applying the tape 35 to the ink discharge surface 10 to protect the water repellent film 34 on the ink discharge surface 10, and only the water repellent film 34 attached to the inner wall of the first nozzle hole 6. Can be removed by plasma treatment, and the hydrophilicity of the nozzle inner wall can be recovered.

  In the first embodiment, one surface of the silicon substrate 3a is etched to form the recess 7a that becomes the second nozzle hole 7, and the surface on which the recess 7a that becomes the second nozzle hole 7 is formed. In order to reduce the thickness of the silicon substrate 3a from the surface opposite to the surface where the support substrate 40 is bonded, the thick silicon substrate 3a is formed when the recess 7a to be the second nozzle hole 7 is formed. Can be used, and the silicon substrate 3a can be prevented from cracking or chipping.

  Furthermore, since there is no process for processing the thinned silicon substrate 3a, it is possible to effectively prevent the silicon substrate 3a from being cracked or chipped. Further, in the step of attaching the support substrate 40 to the silicon substrate 3a, the silicon substrate 3a is filled with resin so that the resin fills the recess 6c serving as the first nozzle hole 6 and the recess 7b serving as the second nozzle hole 7. It is possible to prevent the tip of the nozzle 8 from being chipped when thinning the plate. Furthermore, since the concave portion that becomes the nozzle 8 in the non-penetrating state is formed in the thick silicon substrate 3a, it is possible to prevent helium gas or the like from leaking to the processing surface side and thus making etching impossible.

Embodiment 2. FIG.
FIG. 12 is a perspective view showing an example of a droplet discharge device 150 equipped with the droplet discharge head 100 obtained by the manufacturing method of the first embodiment. A droplet discharge device 150 shown in FIG. 10 is a general inkjet printer. The droplet discharge device 150 can be manufactured by a known manufacturing method. The droplet discharge head 100 obtained in the first embodiment is free from cracks and chips as described above, and the droplet discharge device 100 has high discharge performance.

  In addition, the droplet discharge head 100 obtained by the manufacturing method of Embodiment 1 can manufacture a color filter for a liquid crystal display by changing various droplets in addition to the droplet discharge device 150 shown in FIG. The present invention can also be applied to formation of a light emitting portion of an organic EL display device, discharge of a biological liquid, and the like. Further, the droplet discharge head 100 obtained by the manufacturing method of Embodiment 1 can be used for a piezoelectric drive type droplet discharge device and a bubble jet (registered trademark) type droplet discharge device.

  In addition, the manufacturing method of the droplet discharge head and the manufacturing method of the droplet discharge device of the present invention are not limited to the contents described in the embodiment of the present invention, and are changed within the scope of the idea of the present invention. be able to. For example, in the manufacturing process of FIG. 6L, it is not always necessary to form the peeling layer 41, and it is sufficient that the silicon substrate 3a and the support substrate 40 can be separated. Further, although the case where the droplet discharge head 100 has a three-layer structure has been described as an example, the droplet discharge head 100 may have a four-layer structure.

2 is a longitudinal sectional view showing a cross-sectional configuration of a droplet discharge head according to Embodiment 1. FIG. It is a disassembled perspective view of a droplet discharge head. FIG. 6 is a top view of the nozzle substrate as viewed from the ink ejection surface side. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the longitudinal cross-sectional view which showed the manufacturing process at the time of manufacturing a droplet discharge head. It is the perspective view which showed an example of the droplet discharge apparatus carrying a droplet discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity substrate, 1a Silicon substrate, 2 Electrode substrate, 2a Glass substrate, 3 Nozzle substrate, 3a Silicon substrate, 6 1st nozzle hole, 6a Recessed part used as 1st nozzle hole, 6b Recessed part used as 1st nozzle hole 6c, a concave portion that becomes the first nozzle hole, 7a second nozzle hole, 7a a concave portion that becomes the second nozzle hole, 7b a concave portion that becomes the second nozzle hole, 8 nozzles, 10 ink ejection surface, 11 joint surface, 12 diaphragm, 13 discharge chamber, 13a recess serving as discharge chamber, 14 reservoir, 14a recess serving as reservoir, 15 orifice, 15a recess serving as orifice, 16 insulating film, 17 individual electrode, 18 ink supply hole, 19 recess, 21 Drive circuit, 22 Silicon oxide film, 23 Electrode extraction part, 24 Droplet protection film, 34 Water repellent film, 35 Tape, 40 Support substrate, 41 Release layer, 42 Resin layer, 50 Silicon oxide film, 50a Silicon oxide film, 50b Silicon oxide film, 51 resist, 51a resist, 60 bonded substrate, 60a bonded substrate, 100 droplet discharge head, 150 droplet discharge device.

Claims (16)

A nozzle substrate that forms a recess in the silicon substrate that is a first nozzle hole and a second nozzle hole that communicates with the first nozzle hole and has a diameter larger than the first nozzle hole. A manufacturing method comprising:
Forming the first nozzle hole and the second nozzle hole by dry etching;
Bonding a support substrate to a surface of the silicon substrate where the second nozzle holes are formed using a resin, and filling the resin into the recess;
Thinning the opposite surface of the silicon substrate to which the support substrate is bonded, and opening the first nozzle hole from the thinned silicon substrate;
Removing the resin filled in the concave portion from the portion where the first nozzle hole is opened;
Forming an oxide film and a water repellent film on the thinned surface of the silicon substrate;
And a step of peeling the support substrate from the silicon substrate. A method for manufacturing a nozzle substrate. The method for manufacturing a nozzle substrate according to claim 1, wherein the silicon substrate and the support substrate are bonded together in a vacuum. In the step of bonding a support substrate to the surface of the silicon substrate where the recess is formed using a resin, and filling the resin into the recess,
3. The nozzle substrate according to claim 1, wherein the resin substrate is coated on the support substrate, and then the silicon substrate and the support substrate are bonded together to fill the resin into the concave portion. Production method. The method for manufacturing a nozzle substrate according to claim 1, wherein a release layer that is separated by light is formed between the silicon substrate and the support substrate. The method for manufacturing a nozzle substrate according to claim 4, wherein the support substrate is made of a transparent material. In the step of thinning the opposite surface of the silicon substrate to which the support substrate is bonded,
The method for manufacturing a nozzle substrate according to any one of claims 1 to 5, wherein the silicon substrate is polished by any one of a back grinder, a polisher, and CMP, or a combination thereof. In the step of removing the resin filled in the concave portion from the portion where the first nozzle hole is opened,
The method of manufacturing a nozzle substrate according to claim 1, wherein the resin filled in the recess is removed by O ₂ plasma treatment. In the step of removing the resin filled in the concave portion from the portion where the first nozzle hole is opened,
All of the resin filled in the first nozzle hole;
The method for manufacturing a nozzle substrate according to claim 7, wherein a part or all of the resin filled in the second nozzle hole is removed. The method for manufacturing a nozzle substrate according to claim 1, wherein the first nozzle hole and the second nozzle hole are formed by dry etching using C ₄ F ₈ and SF _6. . The method for manufacturing a nozzle substrate according to claim 1, wherein after the support substrate is peeled from the silicon substrate, the resin is peeled off from the silicon substrate. In the step of peeling the support substrate from the silicon substrate,
The member for protecting the water-repellent film is attached to the thinned surface of the silicon substrate, and then the support substrate is peeled off from the silicon substrate. Nozzle substrate manufacturing method. The method for manufacturing a nozzle substrate according to claim 11, wherein the member for protecting the water repellent film is a tape. The method for manufacturing a nozzle substrate according to claim 11, wherein the member for protecting the water repellent film is a mask. After peeling the support substrate from the silicon substrate,
The method of manufacturing a nozzle substrate according to any one of claims 1 to 13, wherein the inside of the recess is plasma-treated from the surface opposite to the thinned surface of the silicon. A method for manufacturing a droplet discharge head, wherein the droplet discharge head is manufactured using the method for manufacturing a nozzle substrate according to claim 1. A method for manufacturing a droplet discharge device, wherein the method for manufacturing a droplet discharge head according to claim 15 is applied to manufacture a droplet discharge device.

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