JP4670533B2 - Nozzle plate manufacturing method and droplet discharge head manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a nozzle plate having nozzle holes for discharging droplets, a method for manufacturing a droplet discharge head, and a droplet discharge head.

As a droplet discharge head for discharging droplets, for example, an inkjet head mounted on an inkjet recording apparatus is known. Ink jet heads generally include a nozzle plate in which a plurality of nozzle holes for discharging ink droplets are formed, and an ink in a discharge chamber, a reservoir, or the like that is joined to the nozzle plate and communicates with the nozzle holes. And a cavity plate in which a flow path is formed, and an ink droplet is ejected from a selected nozzle hole by applying pressure to the ejection chamber by a driving unit. As a driving means, there are a method using an electrostatic force, a piezoelectric method using a piezoelectric element, a bubble jet (registered trademark) method using a heating element, and the like.
In recent years, there has been an increasing demand for high quality printing, image quality, and the like for inkjet heads, and thus there is a strong demand for higher density and improved ejection performance. Against this background, various devices and proposals have been made for the nozzle portion of an inkjet head.

In an ink jet head, in order to improve ink ejection characteristics, it is desirable to adjust the flow path resistance of the nozzle part and adjust the thickness of the substrate so as to obtain an optimum nozzle length. When producing such a nozzle plate, for example, as shown in Patent Document 1, by performing anisotropic dry etching using ICP (Inductively Coupled Plasma) discharge from one surface of a silicon substrate, the nozzle portion is formed. After forming the first concave portion (the concave portion serving as the nozzle hole injection port portion) and the second concave portion (the concave portion serving as the nozzle hole inlet port portion) having different inner diameters to form two stages, the opposite surface A method for adjusting the length of the nozzle by digging a part of the nozzle by anisotropic wet etching has been adopted.
On the other hand, for example, as shown in Patent Document 2, after the silicon substrate is polished in advance to a desired thickness, the both sides of the silicon substrate are dry-etched, so that the nozzle hole injection port portion and the inlet port portion are formed. There is also a method of forming.

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

  However, as in Patent Document 1, if the discharge surface on which the nozzle hole opens is the bottom surface of the recess that is deeply lowered from the substrate surface, the ink droplet may be bent or the nozzle hole may be clogged. When paper dust, ink, etc. adhere to the bottom surface of the recess, which is the discharge surface, there is a problem that wiping work for wiping the bottom surface of the recess with a rubber piece or felt piece becomes difficult in order to eliminate the paper dust, ink, etc. It was.

  In addition, in the manufacturing method of Patent Document 2, as the density of the ink jet head increases, the thickness of the silicon substrate must be further reduced. However, such a substrate is easily broken during the manufacturing process and is expensive. there were. Furthermore, during dry etching, cooling is performed from the back surface of the substrate with He gas or the like so that the processed shape is stabilized. However, when the nozzle hole penetrates, the He gas may leak and etching may be impossible. For this reason, a recess that becomes a nozzle hole is formed in advance in the silicon substrate, and the silicon substrate is thinned by grinding, etching, or the like after being bonded to a support substrate such as quartz glass using a resin. ) Is used.

  However, since the resin for bonding the support substrate enters the recess that becomes the nozzle hole, the resin is difficult to peel off, the silicon substrate is easily cracked or chipped during the support substrate peeling process, and a resin residue is generated. This was a cause of a significant decrease in yield.

  On the other hand, when water-soluble ink is used in an inkjet head, ink droplets are liable to adhere if the ink repellency of the nozzle surface from which ink is ejected is insufficient, so that the straightness of the ejected ink is impaired and printing is performed. Recording failure such as disturbance may occur. For this reason, ink repellent treatment is performed on the nozzle surface. However, when chemical treatment is necessary to prevent the resin residue, the ink repellent film on the nozzle surface deteriorates at the same time, reducing reliability. There is a problem.

According to the present invention, the silicon substrate is not cracked or chipped during processing, and no foreign matter such as resin or abrasive remains in the nozzle hole, so that the yield and productivity can be improved. It is an object of the present invention to provide a method for manufacturing a nozzle plate for droplet discharge and a method for manufacturing a droplet discharge head.
Further, according to the present invention, when the surface of the nozzle plate is subjected to a liquid repellent treatment, the removal treatment is easy without using a chemical treatment or the like for removing the resin residue, and the liquid repellent film on the discharge surface is not damaged. It is an object to provide a method for manufacturing a nozzle plate and a method for manufacturing a droplet discharge head.

  In order to solve the above-described problem, a method for manufacturing a nozzle plate according to the present invention includes a first concave portion serving as an ejection port portion of a nozzle hole for discharging droplets and an introduction port on one surface of a substrate to be processed. Forming a second concave portion to be a part, forming a weak adhesive layer having a weak adhesive force with a resin in one surface of the substrate to be processed and in the first and second concave portions; A step of bonding a support substrate to the surface of the substrate to be processed on which the weak adhesive layer is formed using the resin, and a step of thinning the substrate to be processed to a required thickness from the other surface; The method includes a step of peeling the support substrate from the substrate to be processed, and a step of removing the resin and the weak adhesive layer from the substrate to be processed.

  As described above, the method for manufacturing a nozzle plate according to the present invention includes a liquid-repellent layer or the like formed on a substrate to be processed on which a first recess serving as an injection port portion of a nozzle hole and a second recess serving as an introduction port portion are formed. After bonding the support substrate with resin via the weak adhesive layer, the substrate to be processed is thinned to the required thickness, making it easier for the support substrate and resin to peel from the substrate to be processed, and making the plate thinner The processed substrate is not cracked or chipped, and no foreign matter such as resin or abrasive remains in the first and second recesses. Therefore, there is an effect that the yield and productivity are greatly improved in the manufacture of the nozzle plate.

In the nozzle plate manufacturing method of the present invention, when the surface of the nozzle plate needs to be liquid repellent, the other surface of the substrate to be processed or the discharge surface region including at least all the nozzle holes may be liquid repellent. A film is formed.
Here, the “ejection surface area” refers to the range of the nozzle surface that covers the wiping operation of the droplet ejection head, not the entire surface of the nozzle plate. That is, it is only necessary that the liquid repellent film is formed in the range of the nozzle surface where damage such as peeling does not occur due to the wiping operation.
In the present invention, since the liquid repellent film is formed on the entire surface of the other surface of the substrate to be processed or on the discharge surface region including at least all the nozzle holes, the discharge liquid does not adhere to the discharge surface and the discharge defect is not caused. Since it does not occur, the droplet discharge characteristics are improved.

Further, the liquid repellent film is preferably formed on an ink-resistant protective film , thereby improving the reliability of the liquid repellent film on the ejection surface.

Moreover, the resin is filled in the first and second recesses by coating the support substrate with the resin and bonding the support substrate in a vacuum.
By performing the bonding of the support substrate in a vacuum, the resin for bonding the support substrate to the substrate to be processed can be completely filled in the first and second recesses, and bubbles and the like are contained in these recesses. Will not remain.

In the step of removing the resin and the weak adhesive layer from the substrate to be processed, the resin is peeled from the substrate to be processed, and then an active gas such as oxygen or carbon dioxide, or an inert gas such as argon or helium. The weak adhesive layer is removed from the first and second recesses by plasma treatment using a gas.
As a result, the bonding surface of the substrate to be processed and the weak adhesive layer in the first and second recesses can be completely removed, the residue of foreign matters such as resin and abrasives can be eliminated, and weak adhesiveness can be eliminated. Since no chemical treatment or the like is used for removing the layer, the liquid-repellent film on the ejection surface is not damaged, and the reliability of the liquid-repellent treatment on the ejection surface is improved. Therefore, the productivity of the nozzle plate is improved.

The resin is coated on the support substrate through a release layer that is separated by light irradiation.
As a result, the release layer is irradiated with light and separated from the resin layer, so that the support substrate can be easily released from the substrate to be processed.

In the step of thinning the substrate to be processed, the processed substrate is polished by a back grinder, a polisher, or a CMP apparatus.
Thereby, the surface (discharge surface) of a to-be-processed substrate can be finished with high precision.

  Further, a light transmissive material is used as the support substrate. Accordingly, light such as laser light can be applied to the peeling layer from the back surface of the support substrate, and the support substrate can be easily peeled from the workpiece substrate.

Further, the first and second recesses are formed by anisotropic dry etching by ICP discharge.
Thereby, the first and second recesses can be processed with high accuracy.

The anisotropic dry etching is performed using C ₄ F ₈ and SF ₆ as etching gases.
C ₄ F ₈ acts to protect the side surfaces of these recesses so that the etching does not proceed in the direction of the side surfaces of the first and second recesses, and SF ₆ acts to promote the vertical etching of these recesses. Therefore, these recesses can be processed with high accuracy perpendicular to the substrate surface.

A method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head using any one of the above-described nozzle plate manufacturing methods.
If a droplet discharge head is manufactured using any one of the above-described nozzle plate manufacturing methods, a droplet discharge head having stable droplet discharge characteristics and a high density can be obtained.

  Hereinafter, embodiments of a droplet discharge head having a nozzle plate to which the present invention is applied will be described with reference to the drawings. Here, an electrostatic drive type inkjet head will be described with reference to FIGS. 1 to 3 as an example of a droplet discharge head. Note that the present invention is not limited to the structure and shape shown in the following drawings, and also for a droplet discharge head and a droplet discharge device that discharge droplets by other different drive methods. Applicable.

  FIG. 1 is an exploded perspective view showing an exploded schematic configuration of the ink jet head according to the present embodiment, and a part thereof is shown in cross section. 2 is a cross-sectional view of the ink jet head showing a schematic configuration of the right half of FIG. 1, and FIG. 3 is a top view of the ink jet head of FIG. 1 and 2 are shown upside down from a state in which they are normally used.

  As shown in FIGS. 1 and 2, the inkjet head (an example of a droplet discharge head) 10 according to this embodiment includes a nozzle plate 1 in which a plurality of nozzle holes 11 are provided at a predetermined pitch, and each nozzle hole 11. The cavity plate 2 is provided with an ink supply path independently, and the electrode substrate 3 on which the individual electrode 31 is disposed facing the vibration plate 22 of the cavity plate 2 is bonded to the cavity plate 2.

The nozzle plate 1 is manufactured from a silicon single crystal substrate (hereinafter also simply referred to as a silicon substrate) thinned to a required thickness (for example, a thickness of about 280 μm to 60 μm) by a manufacturing method described later. Further, an ink repellent film 13 is formed as an example of a liquid repellent film on the entire surface of the nozzle plate 1 or a part thereof, that is, on the ejection surface area including all the nozzle holes 11. The ink repellent film 13 is formed on an ink-resistant protective film 12 made of, for example, a silicon oxide film (SiO ₂ film). The “ejection surface area” is a range that covers the wiping operation of the inkjet head as described above.

  The nozzle holes 11 for ejecting ink droplets are composed of, for example, two-stage cylindrical nozzle holes having different diameters, that is, an ejection port portion 11a having a smaller diameter and an introduction port portion 11b having a larger diameter. It is configured. The injection port portion 11a and the introduction port portion 11b are provided perpendicular to and coaxially with respect to the substrate surface. The injection port portion 11a has a tip opening on the surface of the nozzle plate 1, and the introduction port portion 11b is the nozzle plate 1. Are opened on the back surface (the surface on the bonding side to be bonded to the cavity plate 2).

  As described above, the nozzle hole 11 is configured in two stages from the ejection port portion 11a and the inlet port portion 11b having a larger diameter, thereby aligning the ink droplet ejection direction with the central axis direction of the nozzle hole 11. And stable ink ejection characteristics can be exhibited. That is, there is no variation in the flying direction of ink droplets, there is no scattering of ink droplets, and variations in the ejection amount of ink droplets can be suppressed. In addition, the nozzle density can be increased.

  The cavity plate 2 is made of, for example, a (110) plane-oriented silicon single crystal substrate having a thickness of 525 μm (this substrate is also simply referred to as a silicon substrate hereinafter). The silicon substrate is subjected to anisotropic wet etching to form a recess 25 that becomes the discharge chamber 21 of the ink flow path, a recess 26 that becomes the orifice 23, and a recess 27 that becomes the reservoir 24. A plurality of recesses 25 are independently formed at positions corresponding to the nozzle holes 11. Therefore, as shown in FIG. 2, when the nozzle plate 1 and the cavity plate 2 are joined, the recesses 25 form discharge chambers 21, which communicate with the nozzle holes 11, and are the orifices 23 that are ink supply ports. Both communicate with each other. The bottom wall of the discharge chamber 21 (concave portion 25) is a diaphragm 22.

The recess 26 forms a narrow groove-like orifice 23, and the recess 25 (discharge chamber 21) and the recess 27 (reservoir 24) communicate with each other via the recess 26.
The recess 27 is for storing a liquid material such as ink, and constitutes a reservoir (common ink chamber) 24 common to the ejection chambers 21. The reservoirs 24 (concave portions 27) communicate with all the discharge chambers 21 through the orifices 23, respectively. The orifice 23 (concave portion 26) can also be provided on the back surface of the nozzle plate 1 (the surface on the joint side with the cavity plate 2). Further, a hole penetrating the electrode substrate 3 described later is provided in the bottom of the reservoir 24, and ink is supplied from an ink cartridge (not shown) through the ink supply hole 34 of the hole.

  In addition, as described above, a silicon single crystal substrate having a (110) orientation is used for the cavity plate 2 by performing anisotropic wet etching on the silicon substrate so that the side surfaces of the recesses and the grooves are formed on the upper surface of the silicon substrate. This is because the etching can be performed perpendicularly to the lower surface, whereby the density of the inkjet head can be increased.

An insulating film made of SiO ₂ or TEOS (Tetraethylorthosilicate Tetraethoxysilane) is formed on the entire surface of the cavity plate 2 or at least the surface facing the electrode substrate 3 by thermal oxidation or plasma CVD (Chemical Vapor Deposition). 28 is applied with a film thickness of 0.1 μm. This insulating film 28 is provided for the purpose of preventing dielectric breakdown and short circuit when the ink jet head is driven.

  The electrode substrate 3 is made from a glass substrate having a thickness of about 1 mm, for example. Among them, it is suitable to use a borosilicate heat-resistant hard glass having a thermal expansion coefficient close to that of the silicon substrate of the cavity plate 2. This is because when the electrode substrate 3 and the cavity plate 2 are anodically bonded, the thermal expansion coefficients of the two substrates are close to each other, so that the stress generated between the electrode substrate 3 and the cavity plate 2 can be reduced, and as a result, peeling, etc. This is because the electrode substrate 3 and the cavity plate 2 can be firmly bonded without causing the above problem. The nozzle plate 1 may be a borosilicate glass substrate for the same reason.

  The electrode substrate 3 is provided with a recess 32 at a position on the surface of the cavity plate 2 facing each diaphragm 22. The recess 32 is formed with a depth of about 0.3 μm by etching. And in each recessed part 32, the individual electrode 31 which generally consists of ITO (Indium Tin Oxide: Indium tin oxide) is formed by the thickness of 0.1 micrometer, for example. Therefore, the gap (gap) formed between the diaphragm 22 and the individual electrode 31 is determined by the depth of the recess 32 and the thickness of the insulating film 28 covering the individual electrode 31 and the diaphragm 22. This gap greatly affects the ejection characteristics of the inkjet head. Here, the material of the individual electrode 31 is not limited to ITO, and a metal such as chromium may be used. However, since ITO is transparent, it is generally easy to confirm whether or not a discharge has occurred. ITO is used.

  The individual electrode 31 has a lead part 31a and a terminal part 31b connected to a flexible wiring board (not shown). As shown in FIGS. 1 to 3, these terminal portions 31b are exposed in the electrode extraction portion 30 in which the end portion of the cavity plate 2 is opened for wiring.

  As described above, the nozzle plate 1, the cavity plate 2, and the electrode substrate 3 are bonded together as shown in FIG. That is, the cavity plate 2 and the electrode substrate 3 are joined by anodic bonding, and the nozzle plate 1 is joined to the upper surface (the upper surface in FIG. 2) of the cavity plate 2 by adhesion or the like. Furthermore, the open end of the interelectrode gap formed between the diaphragm 22 and the individual electrode 31 is sealed with a sealing material 35 made of resin such as epoxy. Thereby, moisture and dust can be prevented from entering the gap between the electrodes, and the reliability of the inkjet head 10 can be kept high.

Finally, as shown in a simplified manner in FIGS. 2 and 3, the drive control circuit 4 such as an IC driver is connected to the terminal portion 31 b of each individual electrode 31 and the common electrode 29 provided on the cavity plate 2. They are connected via a wiring board (not shown).
Thus, the ink jet head 10 is completed.

Next, the operation of the inkjet head 10 configured as described above will be described.
The drive control circuit 4 is an oscillation circuit that controls the supply and stop of charges to the individual electrodes 31. This oscillation circuit oscillates at, for example, 24 kHz, and supplies electric charges by applying pulse potentials of, for example, 0 V and 30 V to the individual electrodes 31. When the oscillation circuit is driven and charges are supplied to the individual electrode 31 to be positively charged, the diaphragm 22 is negatively charged and an electrostatic force (Coulomb force) is generated between the individual electrode 31 and the diaphragm 22. Therefore, the diaphragm 22 is attracted to the individual electrode 31 by this electrostatic force and bends (displaces). As a result, the volume of the discharge chamber 21 increases. When the supply of electric charges to the individual electrode 31 is stopped, the diaphragm 22 returns to its original state due to its elastic force, and at this time, the volume of the discharge chamber 21 decreases rapidly. Part of the ink is ejected from the nozzle hole 11 as an ink droplet. When the diaphragm 22 is similarly displaced next, ink is supplied from the reservoir 24 through the orifice 23 into the discharge chamber 21.

As described above, the inkjet head 10 of the present embodiment has a cylindrical injection port portion 11a in which the nozzle holes 11 are perpendicular to the surface (discharge surface) of the nozzle plate 1, and is coaxial with the injection port portion 11a. Since the inlet port portion 11b is provided and has a larger diameter than the jet port portion 11a, the ink droplets can be discharged straight in the direction of the central axis of the nozzle hole 11 and have extremely stable discharge characteristics.
Furthermore, since the cross-sectional shape of the inlet port portion 11b can be formed in a circular shape, a quadrangular shape, or the like, the density of the inkjet head 10 can be increased.

  In addition, the cross-sectional shape of the injection port portion 11a and the introduction port portion 11b of the nozzle hole 11 is not particularly limited, and is formed in a square shape or a circular shape. However, a circular shape is preferable because it is advantageous in terms of discharge characteristics and workability.

Next, a method for manufacturing the inkjet head 10 will be described with reference to FIGS.
4 to 8 are cross-sectional views of the manufacturing process showing the manufacturing method of the nozzle plate 1, and FIGS. 9 and 10 are cross-sectional views of the manufacturing process showing the manufacturing method of the cavity plate 2 and the electrode substrate 3. Here, a method of manufacturing the cavity plate 2 after bonding the silicon substrate 200 to the electrode substrate 3 will be mainly shown.
First, a method for manufacturing the nozzle plate 1 will be described.

(1) Manufacturing Method of Nozzle Plate 1 First, as a substrate to be processed, for example, a silicon substrate 100 having a thickness of 280 μm is prepared, and a SiO ₂ film 101 having a thickness of 1 μm is uniformly formed on the entire surface of the silicon substrate 100. (FIG. 4 (A)). The SiO ₂ film 101 is formed, for example, by setting the silicon substrate 100 in a thermal oxidation apparatus and performing a thermal oxidation process for 4 hours in an oxygen and water vapor mixed atmosphere at an oxidation temperature of 1075 ° C. The SiO ₂ film 101 is used as an etching resistant material for silicon.

Next, a resist 102 is coated on the SiO ₂ film 101 of one surface of the silicon substrate 100 (the surface that is bonded to the cavity plate 2, hereinafter also referred to as “bonded surface”) 100 b, On the surface 100b, a portion 105b that becomes the inlet portion 11b of the nozzle hole 11 is patterned to remove the resist 102 of the portion 105b that becomes the inlet portion 11b (FIG. 4B).
Then, for example, half-etching the SiO ₂ film 101 with a buffered hydrofluoric acid aqueous solution prepared by mixing an aqueous solution with an ammonium fluoride aqueous solution of hydrofluoric acid in a one-to-6, to reduce the SiO ₂ film 101 of the portion 105b of the inlet port portion 11b (FIG. 4 (C)). At this time, the SiO ₂ film 101 on the surface where the resist 102 is not formed (surface on the ejection side, that is, the ejection surface) 100a is also etched to reduce the thickness.
Thereafter, the resist 102 is removed by washing with sulfuric acid or the like (FIG. 4D).

  Next, after removing the resist 102, the resist 106 is coated again on the bonding-side surface 100 b of the silicon substrate 100, and the portion 105 a that becomes the injection port portion 11 a of the nozzle hole 11 is patterned on the bonding-side surface 100 b and sprayed. The resist 106 in the portion 105a that becomes the mouth portion 11a is removed (FIG. 5E).

Then, for example, the SiO ₂ film 101 is 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 open the SiO ₂ film 101 of the portion 105a to be the injection port portion 11a (FIG. 5 (F)). At this time, the SiO ₂ film 101 on the opposite discharge side surface 100a is etched and completely removed.
Next, when the opening of the SiO ₂ film 101 is completed, the resist 106 is removed by washing with sulfuric acid or the like (FIG. 5G).

Next, the dry etching by ICP (Inductively Coupled Plasma) discharge performs anisotropic dry etching of the opening portion of the SiO ₂ film 101 at a depth of, for example, 25 μm vertically to form the injection port portion 11 a of the nozzle hole 11. The recess 107 is formed (FIG. 5H). In this case, for example, C ₄ F ₈ (carbon fluoride) and SF ₆ (sulfur fluoride) may be used as the etching gas, and these etching gases may be used alternately. Here, C ₄ F ₈ is used to protect the side surface of the first concave portion 107 so that the etching does not proceed in the side direction of the first concave portion 107, and SF ₆ is used in the vertical direction of the first concave portion 107. Used to promote etching.

Next, half etching is performed with, for example, a buffered hydrofluoric acid solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed 1: 6 so that only the SiO ₂ film 101 of the portion 105b which becomes the introduction port portion 11b of the nozzle hole 11 is eliminated. (FIG. 6 (I)).
Then, the opening of the SiO ₂ film 101 is again anisotropically dry etched at a depth of, for example, 40 μm by dry etching using ICP discharge to form the second recess 108 that becomes the inlet portion 11b (FIG. 6). (J)).

Next, after the SiO ₂ film 101 remaining on the surface of the silicon substrate 100 is removed with an aqueous hydrofluoric acid solution, the silicon substrate 100 is set in a thermal oxidation apparatus, an oxidation temperature of 1075 ° C., an oxidation time of 4 hours, and a mixed atmosphere of water vapor and oxygen. The film is formed on the side and bottom surfaces of the first recess 107 serving as the injection port portion 11a and the second recess 108 serving as the introduction port portion 11b processed by the ICP dry etching apparatus. A 1 μm thick SiO ₂ film 110 is uniformly formed (FIG. 6K).

  For example, an ink repellent treatment is performed as a method of forming a weak adhesive layer having a weak adhesive force with a resin layer 402 described later on both surfaces of the silicon substrate 100. In this case, for example, an ink repellent material containing fluorine (F) atoms is formed by vapor deposition or dipping to form the ink repellent layer 111 (FIG. 6L). The ink repellent layer 111 is also formed on the side and bottom surfaces of the first recess 107 and the second recess 108.

  Next, a peeling layer 401 is spin-coated on a support substrate 400 made of a transparent material such as glass, and a resin layer 402 is spin-coated thereon. Then, the surface of the support substrate 400 on which the release layer 401 and the resin layer 402 are spin-coated and the surface of the silicon substrate 100 on which the first concave portion 107 and the second concave portion 108 are formed face each other. When the resin is in a softened state, for example, the support substrate 400 and the silicon substrate 100 are bonded together in a vacuum with a vacuum pressure of 0.1 to 0.2 Pa (FIG. 7M). Thereafter, the interior of the first recess 107 and the second recess 108 is filled with the softened resin by opening the vacuum chamber to the atmosphere. Thereafter, the resin layer 402 is cured. Thus, by bonding the support substrate 400 and the silicon substrate 100 under vacuum, the resin can be completely filled in the first recess 107 and the second recess 108, and the remaining of bubbles and the like is prevented. can do.

Here, the release layer 401 and the resin layer 402 will be described.
The peeling layer 401 has a function of causing peeling (referred to as intra-layer peeling or interface peeling) inside the peeling layer 401 or at the interface with the silicon substrate 100 by applying light such as laser light. That is, the release layer 401 is ablated (ablated or removed) due to loss or reduction of the bonding force between atoms or molecules of the material constituting the release layer 401 by receiving light of a certain intensity. It becomes easy to peel. In addition, the release layer 401 receives light of a certain intensity, so that the components in the material constituting the release layer 401 are released as a gas and are separated. In some cases, the vapor is released to cause separation. Thereby, the support substrate 400 can be removed from the silicon substrate 100 thinned in the process of FIG.

  Note that the support substrate 400 is preferably formed using a light-transmitting material (eg, glass). Thus, when the support substrate 400 is peeled from the silicon substrate 100, the release layer 401 is irradiated with light from the back surface of the support substrate 400 (the surface opposite to the surface on which the silicon substrate 100 is bonded) to give sufficient peeling energy. Is possible. Further, the support substrate 400 can be easily peeled from the silicon substrate 100 by two-dimensionally scanning light such as laser light from the back surface of the support substrate 400.

  The material constituting the release layer 401 is not particularly limited as long as it has the functions described above. Specifically, for example, amorphous silicon (a-Si, amorphous silicon), silicon oxide or silicate compound, nitride ceramics such as silicon nitride, aluminum nitride, and titanium nitride, the interatomic bond is broken by light irradiation. Organic polymer materials, metals such as Al, Li, Ti, Mn, In, Sn, Y, La, Ce, Nd, Pr, Gd, or Sm, or alloys containing at least one of these metals. . Among these, as a constituent material of the peeling layer 401, amorphous silicon (a-Si) is preferably used, and the amorphous silicon containing hydrogen (H) is more preferable. By using such a material, when the peeling layer 401 receives light, hydrogen is released and an internal pressure is generated in the peeling layer 401, so that peeling can be promoted. In this case, the hydrogen content in the release layer 401 is preferably about 2 at% or more, and more preferably 2 to 20% at%. In addition, the hydrogen content is the film formation conditions of the release layer 401, for example, when using the CVD method, the gas composition, gas pressure, gas atmosphere, gas flow rate, gas temperature, substrate temperature, input power, etc. It can be adjusted by appropriately setting the conditions.

  The resin layer 402 has a function of absorbing unevenness of the silicon substrate 100 and bonding the silicon substrate 100 and the support substrate 400 together. The material constituting the resin layer 402 is not particularly limited as long as it has a function of bonding the silicon substrate 100 and the support substrate 400, and various resins can be used. More specifically, for example, a curable adhesive such as a thermosetting adhesive or a photocurable adhesive can be used. In addition, the resin layer 402 is preferably composed mainly of a material having high dry etching resistance. Thus, when the silicon substrate 100 is thinned by dry etching to form the nozzle hole, the nozzle hole can be formed by completely penetrating the silicon substrate 100 using the resin layer 402 as an etching stop layer. it can. In addition, the resin layer 402 also has an action of relaxing stress generated in the resin layer 402 due to a difference in coefficient of linear expansion due to a difference in material between the silicon substrate 100 and the support substrate 400 during processing.

  In the present embodiment, the release layer 401 and the resin layer 402 are formed as separate layers, but these layers may be configured as a single layer. For example, as a layer for bonding the silicon substrate 100 and the support substrate 400, a layer having an adhesive force (bonding force) and an effect of causing peeling by light energy, thermal energy, or the like (an effect of reducing the bonding force) is used. May be. In addition, about the material which has such a function, the material of Unexamined-Japanese-Patent No. 2002-338771 is applicable, for example.

Returning to the description of the manufacturing process again with reference to FIG. In FIG. 7M, after the silicon substrate 100 and the support substrate 400 are bonded together, polishing is performed from the discharge surface side of the silicon substrate 100 by a back grinder, a polisher, a CMP (Chemical Mechanical Polishing) apparatus, or the like. The SiO ₂ film 110 at the tip of one recess 107 is removed, and the silicon substrate 100 is thinned (thinned) until the tip opens (FIG. 7N). At this time, for example, if the silicon substrate 100 is ground and thinned to the vicinity of the SiO ₂ film 110 near the tip of the first recess 107 with a back grinder, and then finishing is performed by a polisher or a CMP apparatus, the silicon substrate 100 The surface can be mirror-finished with high accuracy. Furthermore, in this thinning step, the inside of the first recess 107 and the second recess 108 is protected by being filled with the resin of the resin layer 402. The abrasive does not enter the inside, and therefore there is no need for a water washing removal process of the abrasive. As another method for thinning the silicon substrate 100, the opening of the tip of the first recess 107 may be performed by dry etching. In this case, for example, by dry etching using SF ₆ as an etching gas, the silicon substrate 100 is thinned to the vicinity of the tip of the first recess 107, and the SiO ₂ film 110 at the tip of the first recess 107 is exposed to the surface. Then, the SiO ₂ film 110 may be removed by dry etching using CF ₄ or CHF ₃ as an etching gas. At this time, the resin layer 402 serves as an etching stop layer as described above.

Next, an ink-resistant protective film 112 made of a SiO ₂ film is formed to a thickness of 0.1 μm on the ink ejection surface of the silicon substrate 100 by using, for example, a sputtering apparatus (FIG. 7O). Here, the formation of the SiO ₂ film is not limited to the sputtering method as long as it can be performed at a temperature (about 200 ° C.) or less at which the resin layer 402 does not deteriorate. 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.

  Next, the surface of the ink-resistant protective film 112 of the silicon substrate 100 is again subjected to ink repellent treatment (FIG. 7P). For example, an ink-repellent material containing fluorine atoms is formed by vapor deposition or dipping to form the ink-repellent film 113. At this time, since the inside of the first recess 107 and the second recess 108 is protected by being filled with the resin of the resin layer 402, only the surface of the ejection surface is selectively subjected to ink repellent treatment.

Next, laser light or the like is irradiated from the back surface side of the support substrate 400, and the support substrate 400 is peeled off from the peeling layer 401 (FIG. 8Q).
Then, the resin layer 402 is slowly peeled off from the outer periphery using an adhesive tape or the like, and the resin layer 402 is peeled from the silicon substrate 100 (FIG. 8R). At this time, since the ink repellent layer 111 containing fluorine atoms is formed on the bonding surface of the silicon substrate 100 to the support substrate 400 and the inner surfaces of the first recess 107 and the second recess 108, the resin layer 402 The peeling resistance of the silicon substrate 100 can be reduced, there is no breakage such as cracking or chipping of the silicon substrate 100, and resin remains in the bonding surface of the silicon substrate 100, the first recess 107, or the second recess 108. The resin layer 402 can be easily peeled off.

  Next, in order to remove the ink repellent layer 111 in the first concave portion 107 and the second concave portion 108 to be the nozzle hole 11, for example, it is set in a dry etching apparatus, and the inside of the nozzle hole 11 is formed by, for example, argon gas plasma treatment The ink repellent layer 111 is removed (FIG. 8S). Instead of argon gas, an active gas such as oxygen or carbon dioxide gas or an inert gas such as helium can be used.

As described above, the nozzle plate 1 (silicon substrate 100) having the nozzle hole 11 including the injection port portion 11a and the inlet port portion 11b having a larger diameter and having a reduced thickness is manufactured.
If the ink-repellent process is not performed on the ejection surface of the nozzle plate 1, the steps of FIGS. 7O to 7P may be omitted. In the method for manufacturing the nozzle plate 1 of the present embodiment, a borosilicate glass substrate can be used instead of the single crystal silicon substrate.

  As described above, according to the method of manufacturing the nozzle plate 1 of the present embodiment, the first recess 107 serving as the injection port portion 11a of the nozzle hole 11 and the second recess 108 serving as the introduction port portion 11b are previously formed on the silicon substrate. When the silicon substrate 100 is bonded to the support substrate 400 with the resin layer 402, the bonding is performed in a vacuum atmosphere. Therefore, the resin is completely contained in the first and second recesses. Can be filled. Therefore, in the step of thinning the silicon substrate 100, the tip of the first recess 107, that is, the tip of the nozzle can be eliminated, and foreign substances such as abrasives can be prevented from entering the nozzle hole during grinding of the silicon substrate. be able to.

  Furthermore, when the support substrate 400 and then the resin layer 402 are peeled from the silicon substrate 100, the ink repellent layer 111 is formed in the bonding surface of the silicon substrate and the first and second recesses. 402 can be easily peeled off from the silicon substrate, and there is no damage such as cracking of the thinned silicon substrate. Further, the resin can be put into the first and second recesses and the silicon substrate can be attached. It does not remain on the mating surface. Therefore, there is an effect that the manufacturing yield of the nozzle plate is dramatically improved.

  Further, even when it is necessary to perform the ink repellent treatment on the ejection surface, the resin filled in the first and second recesses serves as a protective film, so that extra ink repellent in the nozzle hole. Formation of the film can be prevented. Therefore, there is an effect that the reliability of the ink repellent treatment on the ejection surface is remarkably improved.

If it is necessary to remove the ink repellent layer 111 once formed in the first and second recesses, the ink repellent layer 111 can be easily removed by plasma treatment of Ar or O _{2 with} a dry etching apparatus. Therefore, there is no need for a removal step such as chemical treatment, so that productivity is improved and processing can be performed without damaging the ink repellent film 113 on the ejection surface.

(2) Manufacturing Method of Cavity Plate 2 and Electrode Substrate 3 Here, a method of manufacturing the cavity plate 2 from the silicon substrate 200 after bonding the silicon substrate 200 to the electrode substrate 3 will be described with reference to FIGS. Briefly described.

The electrode substrate 3 is manufactured as follows.
First, a concave portion 32 is formed by etching a glass substrate 300 made of borosilicate glass or the like with a plate thickness of about 1 mm with hydrofluoric acid using, for example, a gold / chromium etching mask. Note that the recess 32 has a groove shape slightly larger than the shape of the individual electrode 31, and a plurality of the recesses 32 are formed for each individual electrode 31.
Then, an individual electrode 31 made of ITO (Indium Tin Oxide) is formed inside the recess 32 by sputtering, for example.
Thereafter, the hole 34a to be the ink supply hole 34 is formed by a drill or the like, whereby the electrode substrate 3 is manufactured (FIG. 9A).

  Next, after both surfaces of the silicon substrate 200 having a thickness of, for example, 525 μm are mirror-polished, a silicon oxide film (insulating film) made of TEOS having a thickness of 0.1 μm is formed on one surface of the silicon substrate 200 by plasma CVD (Chemical Vapor Deposition). 28 is formed (FIG. 9B). Note that before the silicon substrate 200 is formed, a boron doped layer for forming the thickness of the diaphragm 22 with high accuracy may be formed using an etching stop technique. Etching stop is defined as a state in which bubbles generated from the etching surface are stopped, and in actual wet etching, it is determined that the etching is stopped when the generation of bubbles is stopped.

Then, the silicon substrate 200 and the electrode substrate 3 manufactured as shown in FIG. 9A are heated to, for example, 360 ° C., and the anode is connected to the silicon substrate 200 and the electrode substrate 3 is connected to the cathode, and the voltage is about 800V. A voltage is applied to join by anodic bonding (FIG. 9C).
After anodic bonding of the silicon substrate 200 and the electrode substrate 3, the silicon substrate 200 in a bonded state is etched with an aqueous potassium hydroxide solution or the like, thereby reducing the thickness of the silicon substrate 200 to, for example, 140 μm (FIG. 9 ( D)).

Next, a TEOS film having a thickness of, for example, 0.1 μm is formed on the entire upper surface of the silicon substrate 200 (the surface opposite to the surface to which the electrode substrate 3 is bonded) by plasma CVD.
Then, the TEOS film is patterned with a resist for forming a recess 25 to be the discharge chamber 21, a recess 26 to be the orifice 23, and a recess 27 to be the reservoir 24, and the TEOS film in these portions is removed by etching.
Then, each said recessed part 25-27 is formed by etching the silicon substrate 200 with potassium hydroxide aqueous solution etc. (FIG.10 (E)). At this time, the portion that becomes the electrode extraction portion 30 for wiring is also etched and thinned. In the wet etching step of FIG. 10E, for example, a 35% by weight potassium hydroxide aqueous solution can be used first, and then a 3% by weight potassium hydroxide aqueous solution can be used. Thereby, surface roughness of the diaphragm 22 can be suppressed.

After the etching of the silicon substrate 200 is completed, the TEOS film formed on the upper surface of the silicon substrate 200 is removed by etching with a hydrofluoric acid aqueous solution (FIG. 10F).
Next, a TEOS film (insulating film 28) is formed to a thickness of, for example, 0.1 μm by plasma CVD on the surface of the silicon substrate 200 where the recesses 25 to be the discharge chambers 21 are formed (FIG. 10G).
Thereafter, the electrode extraction unit 30 is opened by RIE (Reactive Ion Etching) or the like. Further, laser processing is performed from the hole portion that becomes the ink supply hole 34 of the electrode substrate 3 to penetrate the bottom portion of the concave portion 27 that becomes the reservoir 24 of the silicon substrate 200, thereby forming the ink supply hole 34 (FIG. 10H). . Further, the open end portion of the interelectrode gap between the diaphragm 22 and the individual electrode 31 is sealed by filling a sealing material (not shown) such as an epoxy resin. Further, as shown in FIGS. 1 and 2, the common electrode 29 is formed on the end of the upper surface of the silicon substrate 200 (the surface on the bonding side with the nozzle plate 1) by sputtering.

As described above, the cavity plate 2 is manufactured from the silicon substrate 200 bonded to the electrode substrate 3.
Finally, the main body of the inkjet head 10 shown in FIG. 2 is manufactured by joining the nozzle plate 1 manufactured as described above to the cavity plate 2 by bonding or the like.

  According to the method for manufacturing the inkjet head 10 of the present embodiment, the cavity plate 2 is produced from the silicon substrate 200 bonded to the electrode substrate 3 produced in advance. Therefore, even if the cavity plate 2 is thinned, it is not cracked or chipped, and handling becomes easy. Therefore, the yield is improved as compared with the case where the cavity plate 2 is manufactured alone.

  In the above embodiment, the inkjet head, its nozzle plate, and the manufacturing method thereof have been described. However, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the idea of the present invention. Can do. For example, by changing the liquid material ejected from the nozzle holes, in addition to inkjet printers, the production of color filters for liquid crystal displays, the formation of light-emitting portions of organic EL display devices, the microarray of biomolecule solutions used for genetic testing, etc. It can be used as a droplet discharge device for various uses such as manufacture of

1 is an exploded perspective view showing a schematic configuration of an inkjet head according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the inkjet head showing a schematic configuration of the right half of FIG. 1. FIG. 3 is a top view of the inkjet head of FIG. 2. Sectional drawing of the manufacturing process which shows the manufacturing method of a nozzle plate. Sectional drawing which shows the manufacturing process following FIG. Sectional drawing which shows the manufacturing process following FIG. Sectional drawing which shows the manufacturing process following FIG. Sectional drawing which shows the manufacturing process following FIG. Sectional drawing of the manufacturing process which shows the manufacturing method of a cavity plate and an electrode substrate. Sectional drawing which shows the manufacturing process following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle plate, 2 Cavity plate, 3 Electrode board | substrate, 4 Drive control circuit, 10 Inkjet head, 11 Nozzle hole, 11a Ejection port part, 11b Introduction port part, 12 Ink-resistant protective film, 13 Ink-repellent film, 21 Discharge chamber, 22 Diaphragm, 23 Orifice, 24 Reservoir, 25 Recess, 26 Recess, 27 Recess, 28 Insulating film, 29 Common electrode, 30 Electrode take-out part, 31 Individual electrode, 31a Lead part, 31b Terminal part, 32 Recess, 34 Ink supply Hole, 35 sealing material, 100 silicon substrate, 101 SiO ₂ film, 102 resist, 106 resist, 107 first recess, 108 second recess, 110 SiO ₂ film, 111 ink repellent layer, 112 ink resistant protective film, 113 Ink repellent film, 200 Silicon substrate, 300 Glass substrate, 400 Support substrate, 401 Peeling , 402 resin layer.

Claims (11)

Forming, on one surface of the substrate to be processed, a first recess serving as an injection port portion of a nozzle hole for discharging a droplet and a second recess serving as an introduction port portion;
Forming a weak adhesive layer having a low adhesive force with a resin in one surface of the substrate to be processed and the first and second recesses;
Bonding the support substrate to the surface of the substrate to be processed on which the weak adhesive layer has been formed using the resin;
Thinning the substrate to be processed to a required thickness from the other surface;
Peeling the support substrate from the substrate to be processed;
Removing the resin and the weak adhesive layer from the substrate to be processed;
A method for producing a nozzle plate, comprising:   2. The method of manufacturing a nozzle plate according to claim 1, further comprising a step of forming a liquid repellent film on the entire other surface of the substrate to be processed or on a discharge surface region including at least all of the nozzle holes. 3. The method of manufacturing a nozzle plate according to claim 2, wherein the liquid repellent film is formed on an ink-resistant protective film .   4. The resin is filled in the first and second recesses by coating the resin on the support substrate and bonding the support substrate in a vacuum. The manufacturing method of the nozzle plate in any one of.   In the step of removing the resin and the weak adhesive layer from the substrate to be processed, after the resin is peeled from the substrate to be processed, an active gas such as oxygen or carbon dioxide, or an inert gas such as argon or helium is used. 5. The method of manufacturing a nozzle plate according to claim 1, wherein the weak adhesive layer is removed from the first and second recesses by the plasma treatment used. 6.   5. The method of manufacturing a nozzle plate according to claim 4, wherein the resin is coated on the support substrate through a release layer that is separated by light irradiation.   The nozzle plate manufacturing method according to claim 1, wherein in the step of thinning the substrate to be processed, the processed substrate is polished by a back grinder, a polisher, or a CMP apparatus.   The method for manufacturing a nozzle plate according to claim 1, wherein a light transmissive material is used as the support substrate.   9. The method of manufacturing a nozzle plate according to claim 1, wherein the first and second recesses are formed by anisotropic dry etching using ICP discharge. The anisotropic dry etching method according to claim 9, wherein the nozzle plate and performing using C ₄ F ₈ and SF ₆ as an etching gas.   A method for manufacturing a droplet discharge head, wherein the droplet discharge head is manufactured using the method for manufacturing a nozzle plate according to claim 1.

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