JP2005231274A - Method of manufacturing inkjet head, inkjet head, and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an inkjet head with a high yield. <P>SOLUTION: This method of manufacturing the inkjet head comprises a process of forming a recessed section 6b to be a first nozzle hole part 6 on a silicon substrate 30 to be a nozzle substrate 4 by an anisotropic etching process, a process of forming an etching mask 33 at a side face and a bottom face of the recessed section 6b to be at least the first nozzle hole part 6, a process of bonding a support substrate 40 to the silicon substrate 30 on the face having the recessed section 6b formed thereon, a process of rubbing the silicon substrate 30 from the face opposite the face having the support substrate 40 bonded thereto, a process of forming a second nozzle hole part 7 on the rubbed face by an etching process, and a process of separating the support substrate 40 from the silicon substrate 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet head manufacturing method, an ink jet head, and an ink jet recording apparatus, and more particularly to a method for manufacturing an ink jet head having a high yield.

  An ink jet recording apparatus has many advantages such as high-speed printing, extremely low noise during recording, high degree of freedom of ink, and use of inexpensive plain paper. In recent years, so-called ink-on-demand ink jet recording apparatuses, which eject ink droplets only when recording is necessary, have become mainstream among ink jet recording apparatuses. This ink-on-demand ink jet recording apparatus has an advantage that it does not require collection of ink droplets unnecessary for recording.

  This ink-on-demand ink jet recording apparatus includes a so-called electrostatic drive ink jet recording apparatus that uses electrostatic force as a driving means as a method of ejecting ink droplets. In addition, there are so-called piezoelectric drive type ink jet recording apparatuses that use piezoelectric elements (piezo elements) as driving means, and so-called jibble jet (registered trademark) type ink jet recording apparatuses that use heating elements and the like.

In the ink jet recording apparatus as described above, ink droplets are generally ejected from nozzles of an ink jet head. There are two methods for providing nozzles in an ink jet head: a side eject type that ejects ink droplets from the side surface of the ink jet head, and a face eject type that ejects ink droplets from the surface side of the ink jet head.
In the face eject type ink jet head, it is desirable to adjust the thickness of the nozzle substrate so as to optimize the length of the nozzle by adjusting the flow resistance of the nozzle hole.

  In the conventional method of manufacturing a nozzle plate for a face eject type inkjet head, the first nozzle hole and the second nozzle hole are formed by dry etching from both sides of the silicon substrate after the silicon substrate is ground to a desired thickness. (For example, refer patent document 1).

In a conventional face ejection type nozzle (inkjet head) nozzle forming method, a first nozzle hole and a second nozzle having different inner diameters are formed by anisotropic dry etching using ICP discharge from one surface of a silicon substrate. After forming the holes in two stages, the opposite surface was dug down by anisotropic wet etching to adjust the length of the nozzle (for example, see Patent Document 2).
Japanese Patent Laid-Open No. 9-57981 (FIGS. 1 and 2) Japanese Patent Laid-Open No. 11-28820 (FIGS. 1 to 4)

In a conventional method of manufacturing a nozzle plate for an inkjet head (see, for example, Patent Document 1), before forming the first nozzle hole and the second nozzle hole by dry etching, the silicon substrate is ground and thinned. There has been a problem that the silicon substrate may be broken or chipped during the manufacturing process. In addition, this manufacturing method has a problem in that the manufacturing cost increases because the yield decreases.
Furthermore, in this method of manufacturing a nozzle plate for an inkjet head, cooling is performed with helium gas or the like from the opposite side of the processing surface of the nozzle plate in order to stabilize the processing shape during dry etching processing. And the like leaks to the processed surface side, which makes etching impossible.

  Further, in the conventional nozzle forming method of the ejecting apparatus (see, for example, Patent Document 2), the ejection surface where the first nozzle hole opens is formed at a position that is deeply lowered from the substrate surface. There was a problem that it would turn. Also, with such a structure, there is a problem that it is difficult to perform wiping work for removing paper dust, ink, and the like that cause nozzle clogging from the ejection surface with rubber pieces or felt pieces.

  The present invention provides an inkjet head manufacturing method that can use a relatively thick silicon substrate and that has a high yield, an inkjet head that is manufactured by the inkjet head manufacturing method, and an inkjet recording apparatus equipped with the inkjet head. The purpose is to provide.

An inkjet head manufacturing method according to the present invention includes a nozzle substrate made of silicon subjected to predetermined processing and having a plurality of nozzles, and each nozzle includes at least a first nozzle hole portion and the first nozzle. A method of manufacturing an inkjet head having a second nozzle hole portion communicating with a hole portion, the step of forming a concave portion to be a first nozzle hole portion in a silicon substrate to be a nozzle substrate by anisotropic etching, and at least A step of forming an etching mask on the side surface and bottom surface of the concave portion serving as the first nozzle hole portion, a step of attaching a support substrate to the surface of the silicon substrate where the concave portion serving as the first nozzle hole portion is formed, and a support A step of grinding the silicon substrate from the surface opposite to the bonded surface of the substrate, and a second nozzle hole portion on the surface ground by etching A step of forming a supporting substrate and a step of separating from the silicon substrate.
Since the support substrate is bonded to the surface of the silicon substrate where the concave portion serving as the first nozzle hole portion is formed, and the silicon substrate is ground from the surface opposite to the bonded surface of the support substrate, relatively thick silicon is used. A substrate can be used, and the silicon substrate can be prevented from cracking or chipping during the manufacturing process. In addition, since the support substrate is bonded to the silicon substrate, it is possible to prevent helium gas from leaking to the processing surface side when the nozzle passes through and preventing etching from being performed.

In the method of manufacturing an ink jet head according to the present invention, the support substrate is a transparent substrate.
For example, if a transparent substrate made of glass or the like is used as the support substrate, when the second nozzle hole portion is formed, the alignment mark provided on the silicon substrate can be seen with the double-sided aligner, and the second nozzle hole Patterning of the resist in the portion can be performed with high accuracy.

In addition, in the method of manufacturing an inkjet head according to the present invention, a resist is used when a support substrate is bonded to the silicon substrate.
If the silicon substrate and the support substrate are bonded together using a resist, the bonding becomes easy. Further, the silicon substrate and the support substrate can be easily separated by dissolving the resist.

The method for manufacturing an inkjet head according to the present invention is to manufacture a plurality of nozzle substrates from a single silicon substrate.
Since a plurality of nozzle substrates are manufactured from one silicon substrate, a large number of nozzle substrates can be manufactured, and the manufacturing cost can be reduced.

In addition, in the method for manufacturing an ink jet head according to the present invention, a concave crater is formed on the silicon substrate, and a concave portion to be a first nozzle hole portion is formed in the crater portion.
In order to form the concave portion that becomes the first nozzle hole portion in the concave crater portion, for example, the peripheral portion of the nozzle is worn by contact with the printing paper, or the water repellent layer applied to the periphery of the nozzle is worn. It can be prevented from being trapped.
Further, since the depth of the crater is relatively shallow, ink droplets are not bent during the flight and wiping work is not difficult.

In the inkjet head manufacturing method according to the present invention, the etching mask is made of a silicon oxide film.
If an etching mask made of a silicon oxide film is formed, a highly accurate etching mask can be easily formed.

Moreover, the manufacturing method of the inkjet head which concerns on this invention forms said etching mask by thermal oxidation.
If the etching mask is formed by thermal oxidation, the etching mask can be easily formed as compared with CVD (Chemical Vapor Deposition) or the like.

In the method of manufacturing an ink jet head according to the present invention, the anisotropic etching for forming the concave portion that becomes the first nozzle hole portion is dry etching.
By forming the concave portion serving as the first nozzle hole portion by dry etching, a highly accurate concave portion can be formed in a short time.

In the method of manufacturing an ink jet head according to the present invention, the anisotropic etching for forming the concave portion to be the first nozzle hole portion is dry etching by ICP discharge.
By forming the concave portion serving as the first nozzle hole portion by dry etching using ICP (Inductively Coupled Plasma) discharge, a highly accurate concave portion can be formed in a short time.

In the inkjet head manufacturing method according to the present invention, the etching for forming the second nozzle hole portion is dry etching.
By forming the second nozzle hole portion by dry etching, the second nozzle hole portion having a diameter larger than that of the first nozzle hole portion can be formed with high accuracy in a short time.

An inkjet head according to the present invention is manufactured by any one of the above-described inkjet head manufacturing methods.
Since the ink jet head is manufactured by any one of the above-described ink jet head manufacturing methods, the nozzle substrate is free of cracks and chips and has high ink ejection performance.

An ink jet recording apparatus according to the present invention is equipped with the above ink jet head.
Since the above-described ink jet head having high ink ejection performance is mounted, the ink jet recording apparatus has high printing performance.

Embodiment 1. FIG.
FIG. 1 is a longitudinal sectional view showing an ink jet head according to Embodiment 1 of the present invention. In FIG. 1, the drive circuit 21 is schematically shown. Further, in FIG. 1, as an example of the ink jet head, a face eject type ink jet head by an electrostatic driving method is shown.
The inkjet head 1 according to the first embodiment is mainly configured by bonding a cavity substrate 2, an electrode substrate 3, and a nozzle substrate 4. The nozzle substrate 4 is made of silicon, and for example, a nozzle 8 having a cylindrical first nozzle hole portion 6 and a bell-shaped second nozzle hole portion 7 is formed. The first nozzle hole portion 6 is formed on the ink discharge surface 10 (the surface opposite to the bonding surface 11 with the cavity substrate 2), and the second nozzle hole portion 7 is the first nozzle hole. The diameter communicates with the portion 6 and increases toward the joint surface 11.
The nozzle substrate 4 is preferably made of single crystal silicon so that predetermined processing described later can be easily performed.

  The cavity substrate 2 is made of, for example, single crystal silicon, and has a plurality of recesses serving as discharge chambers 13 whose bottom wall is the diaphragm 12. The plurality of discharge chambers 13 are formed side by side on the back side or the front side of the page in FIG. In addition, the cavity substrate 2 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. Furthermore, an insulating film 16 made of silicon oxide is formed on the entire surface of the cavity substrate 2 by, for example, thermal oxidation. This insulating film 16 is provided in order to prevent dielectric breakdown or short circuit when the inkjet head 1 is driven.

  An electrode substrate 3 made of, for example, borosilicate glass is bonded to the cavity substrate 12 side of the cavity substrate 2. A plurality of electrodes 17 facing the diaphragm 12 are formed on the electrode substrate 3. The 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 3. 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.

In the first embodiment, a method for manufacturing the nozzle substrate 4 will be mainly described. In the nozzle substrate 4 shown in FIG. 1, a concave crater 20 is formed on the ink ejection surface. The crater 20 is formed at the position of the first nozzle hole portion 8. For example, when the printing paper and the nozzle substrate 4 come into contact with each other, the peripheral portion of the nozzle 8 is worn or applied to the peripheral portion of the nozzle 8. It is provided to prevent the water repellent layer from being worn away.
In the inkjet head according to the first embodiment, the central axes of the first nozzle hole portion 6 and the second nozzle hole portion 7 coincide with each other with high accuracy.

Here, the operation of the inkjet head shown in FIG. 1 will be described. A drive circuit 21 is connected to the cavity substrate 2 and each electrode 17. When a pulse voltage is applied between the cavity substrate 2 and the electrode 17 by the drive circuit 21, the diaphragm 12 bends toward the electrode 17, and droplets of ink or the like that have accumulated in the reservoir 14 enter the discharge chamber 13. Flows in. When the voltage applied between the cavity substrate 2 and the electrode 17 disappears, the diaphragm 12 returns to its original position, the pressure inside the discharge chamber 13 increases, and a droplet such as ink is discharged from the nozzle 8. Is done.
In the first embodiment, an electrostatic drive type ink jet head is shown as an example of the ink jet head. However, a method for manufacturing the ink jet head shown in the first embodiment is a piezoelectric drive method, a jibble jet (registered trademark) method, or the like. The present invention can also be applied to the inkjet head.

FIG. 2 is a top view of the nozzle substrate 4 as viewed from the ink ejection surface 10 side. As shown in FIG. 2, a plurality of first nozzle hole portions 6 are opened on the discharge surface 10 side of the nozzle substrate 4. The second nozzle hole portion 7 is formed on the back side of the paper surface of each of the first nozzle hole portions 6 in FIG. Further, the discharge chamber 13 of the cavity substrate 2 is formed for each of the first nozzle hole portions 6, and each discharge chamber 13 is elongated in the direction of the line AA in FIG.
Further, a concave crater 20 is formed around the first nozzle hole portion 6 of the ink discharge surface 10.

3, 4 and 5 are longitudinal sectional views showing the manufacturing process of the ink-jet head according to Embodiment 1 of the present invention. 3, 4, and 5, only the peripheral portion of one nozzle substrate 4 of the silicon substrate 30 to be the nozzle substrate 4 is shown. 3, 4, and 5 show a cross section taken along line AA in FIG. 2.
First, for example, a silicon substrate 30 having a thickness of 525 μm is prepared, and silicon oxide films 31 are uniformly formed on both surfaces of the silicon substrate 30 (FIG. 3A). The silicon oxide film 31 is formed, for example, 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.

Then, a resist (not shown) is applied to one surface of the silicon substrate 30 to pattern the portion 20a that becomes the crater 20, and the silicon oxide film 31 in this portion is thinned by half etching. This half etching is performed using, for example, a buffered hydrofluoric acid aqueous solution (a mixed solution of a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution). Thereafter, the resist formed on one surface of the silicon substrate 30 is once peeled off. Then, a resist (not shown) is applied again to the same surface of the silicon substrate 30, and the portion 6 a to be the first nozzle hole portion 6 is patterned, and etched by, for example, the above buffered hydrofluoric acid aqueous solution. The silicon oxide film 31 is removed (FIG. 3B). The portion 6 a that becomes the first nozzle hole portion 6 is formed in the portion 20 a that becomes the crater 20. In the etching, the silicon oxide film 31 on the surface opposite to the surface coated with the resist is not etched.
Thereafter, all the resist applied to the silicon substrate 30 is peeled off.

After that, anisotropic etching is performed from the portion 6a that becomes the first nozzle hole portion 6 by dry etching by ICP discharge to form, for example, a recess having a depth of 20 μm. CF ₂ and SF ₆ can be used alternately as an etching gas for this anisotropic dry etching. At this time, CF ₄ is used to protect the side surface of the recess so that the etching does not proceed in the direction of the side surface of the recess, and SF ₆ is used to promote the etching in the vertical direction of the recess.
Then, the silicon oxide film 31 is half-etched with a buffered hydrofluoric acid aqueous solution or the like so that only the silicon oxide film 31 in the portion 20a to be the crater 20 is removed. Then, the portion 20a to be the crater 20 and the portion 6a to be the first nozzle hole portion 6 are anisotropically etched by a depth of, for example, 5 μm in the vertical direction by dry etching using ICP discharge. Thereby, the recessed part 6b used as the 1st nozzle hole part 6 and the crater 20 are formed (FIG.3 (C)).

Next, an etching mask 33 made of a silicon oxide film is uniformly formed on both surfaces of the silicon substrate 30 with a thickness of 1 μm, for example (FIG. 3D). The etching mask 33 is formed, for example, by performing 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. The etching mask 33 is also formed on the side surface and the bottom surface of the recess 6 b to be the first nozzle hole portion 6 and the crater 20.
Then, a resist (not shown) is applied to the surface of the silicon substrate 30 where the concave portion 6b to be the first nozzle hole portion is formed, and the support substrate 40 is bonded to this surface (FIG. 4E). At this time, the resist functions as an adhesive, and the support substrate 40 is bonded to the silicon substrate 30 before the resist dries. The support substrate 40 is made of, for example, glass and is a transparent substrate.

Then, the surface of the silicon substrate 30 opposite to the surface to which the support substrate 40 is bonded is ground to reduce the thickness of the silicon substrate 30 to, for example, 70 μm (FIG. 4F). This grinding may be, for example, mechanical grinding, and it is desirable to remove the work-affected layer by etching after mechanical grinding.
Thereafter, a resist 41 is applied to the ground surface of the silicon substrate 30, and a portion 7a to be the second nozzle hole portion 7 is patterned (FIG. 4G). Although a mask is used when patterning this resist, since the support substrate 40 is a transparent substrate, alignment can be performed while looking at an alignment mark (not shown) provided on the silicon substrate 30 with a double-sided aligner. Can be patterned.

Then, the second nozzle hole portion 7 is formed with a depth of 45 μm, for example, by dry etching using the resist 41 as an etching mask (FIG. 4H). As this dry etching, dry etching by ICP discharge can be used, and XeF ₂ (xenon fluoride) or SF ₂ can be used as an etching gas. When XeF ₂ or SF ₂ is used as an etching gas, isotropic etching occurs and the second nozzle hole portion 7 has a bell shape (or a hemispherical shape). The second nozzle hole portion 7 may be formed by anisotropic etching. In this case, the second nozzle hole portion 7 has a cylindrical shape.
In the step of FIG. 4H, since the support substrate 40 is bonded to the silicon substrate 30, when the second nozzle hole portion 7 is formed by dry etching, a recess that becomes the first nozzle hole portion 6 is formed. Even when the silicon oxide film 33 (see FIG. 4H) on the bottom surface of 6b is broken, helium gas for cooling does not leak to the second nozzle hole portion 7 side.

Thereafter, the support substrate 40 bonded to the silicon substrate 30 is separated from the silicon substrate 30 by dissolving a resist (not shown) (FIG. 5I). At this time, a mixed solution of sulfuric acid and hydrogen peroxide water or the like can be used as a solution for dissolving the resist. Note that the resist 41 is also removed in the step of FIG.
Then, the etching mask 33 formed on the silicon substrate 30 is completely removed with a hydrofluoric acid aqueous solution or the like to form an ink-resistant protective film made of silicon oxide or the like on the entire surface of the silicon substrate 30, and the first nozzle hole portion 6. Ink repellent treatment is performed on the surface on which the ink is formed (ink ejection surface 10). Finally, the silicon substrate 30 is cut with a dicing apparatus to complete individual nozzle substrates 4 (FIG. 5J). Thereby, a plurality of nozzle substrates 4 can be manufactured from one silicon substrate 30.

In addition, you may form the recessed part 6b and the crater 20 which become the 1st nozzle hole part 6 by changing the manufacturing process of said FIG. 3 (A) from FIG. 3 (C) as follows. First, a resist is applied to the ink discharge surface 10 side of the silicon substrate 30, and a portion that becomes the crater 20 is patterned. Then, for example, the crater 20 having a depth of 5 μm is dry-etched using this resist as an etching mask, and the resist is once removed. Then, a resist is applied again to the ink ejection surface 10 side of the silicon substrate 30 to pattern the portion that becomes the first nozzle hole portion, and for example, the recess that becomes the first nozzle hole portion is dry-etched at a depth of 20 μm.
However, in this manufacturing process, when the resist is applied and the portion that becomes the first nozzle hole portion is patterned, there is a possibility that the resist will break at the step portion of the crater 20, so that the silicon oxide as described above The manufacturing method for forming the film 31 is more desirable.

In the first embodiment, the support substrate 40 is bonded to the surface of the silicon substrate 30 where the concave portion 6b to be the first nozzle hole portion 6 is formed, and the surface opposite to the bonded surface of the support substrate 40 is used. Since the silicon substrate 30 is ground, a relatively thick silicon substrate 30 can be used, and the silicon substrate 30 can be prevented from being cracked or chipped during the manufacturing process. Further, since the support substrate 40 is bonded to the silicon substrate 30, it is possible to prevent helium gas from leaking to the processing surface side when the nozzle 8 penetrates, and etching from being impossible.
In addition, since a transparent substrate made of glass or the like is used as the support substrate 40, when the second nozzle hole portion 7 is formed, the alignment marks provided on the silicon substrate 30 can be seen with the double-sided aligner, Patterning of the resist 41 in the portion 7a to be the nozzle hole portion 7 can be performed with high accuracy.

  In FIG. 1 of the first embodiment, an electrostatic drive type ink jet head is shown as an example of the ink jet head. However, the method of manufacturing the ink jet head shown in the first embodiment is characterized by the method of manufacturing the nozzle substrate. The present invention can also be applied to an inkjet head such as a piezoelectric drive system or a Jibble Jet (registered trademark) system.

Embodiment 2. FIG.
FIG. 6 is a diagram showing an example of an ink jet recording apparatus according to Embodiment 2 of the present invention. An ink jet recording apparatus 100 shown in FIG. 6 is an ink jet printer, and is equipped with an ink jet head obtained by the ink jet head manufacturing method of the first embodiment. Since the inkjet head obtained by the inkjet head manufacturing method of Embodiment 1 includes a nozzle substrate having high ink ejection performance, the inkjet recording apparatus 100 of Embodiment 2 has high printing performance.

  In addition to the ink jet printer as shown in FIG. 6, the ink jet recording apparatus according to Embodiment 2 of the present invention includes an organic electroluminescence display device manufacturing apparatus, a liquid crystal display device color filter manufacturing apparatus, and a DNA device manufacturing process. There are devices.

1 is a longitudinal sectional view showing an inkjet head according to Embodiment 1 of the present invention. FIG. 4 is a top view of the nozzle substrate as viewed from the ink ejection surface side. FIG. 3 is a longitudinal sectional view showing a manufacturing process of the inkjet head according to the first embodiment. FIG. 4 is a longitudinal sectional view showing a manufacturing process that follows the manufacturing process of FIG. 3. FIG. 5 is a longitudinal sectional view showing a manufacturing process that follows the manufacturing process of FIG. 4. FIG. 5 is a diagram illustrating an example of an ink jet recording apparatus according to a second embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head, 2 cavity board | substrate, 3 electrode board | substrate, 4 nozzle board | substrate, 6 1st nozzle hole part, 7 2nd nozzle hole part, 8 nozzle, 10 ink discharge surface, 11 joint surface, 12 diaphragm, 13 discharge Chamber, 14 Reservoir, 15 Orifice, 16 Insulating film, 17 Electrode, 18 Ink supply hole, 20 Crater, 21 Drive circuit, 30 Silicon substrate, 40 Support substrate, 100 Inkjet recording apparatus.

Claims (12)

A nozzle substrate made of silicon subjected to predetermined processing and having a plurality of nozzles, each nozzle being at least a first nozzle hole portion and a second nozzle hole portion communicating with the first nozzle hole portion A method of manufacturing an inkjet head having
Forming a recess serving as a first nozzle hole in the silicon substrate serving as the nozzle substrate by anisotropic etching; and forming an etching mask at least on the side and bottom surfaces of the recess serving as the first nozzle hole. And a step of bonding a support substrate to a surface of the silicon substrate on which a concave portion serving as a first nozzle hole portion is formed, and grinding the silicon substrate from a surface opposite to the bonded surface of the support substrate An ink jet head manufacturing method comprising: a step, a step of forming a second nozzle hole portion on the ground surface by etching, and a step of separating the support substrate from the silicon substrate.   The method for manufacturing an ink jet head according to claim 1, wherein the support substrate is a transparent substrate.   3. The method of manufacturing an ink jet head according to claim 1, wherein a resist is used when the support substrate is bonded to the silicon substrate.   The method of manufacturing an ink jet head according to claim 1, wherein a plurality of nozzle substrates are manufactured from a single silicon substrate.   5. The method of manufacturing an ink jet head according to claim 1, wherein a concave crater is formed on the silicon substrate, and a concave portion to be the first nozzle hole portion is formed in the crater portion. .   6. The method of manufacturing an ink jet head according to claim 1, wherein the etching mask is made of a silicon oxide film.   The method of manufacturing an ink jet head according to claim 6, wherein the etching mask is formed by thermal oxidation.   The method for manufacturing an ink jet head according to claim 1, wherein the anisotropic etching for forming the concave portion to be the first nozzle hole portion is dry etching.   9. The method of manufacturing an ink jet head according to claim 8, wherein the anisotropic etching for forming the concave portion to be the first nozzle hole portion is dry etching by ICP discharge.   The method for manufacturing an ink jet head according to claim 1, wherein the etching for forming the second nozzle hole portion is dry etching.   An ink jet head manufactured by the method for manufacturing an ink jet head according to claim 1. An ink jet recording apparatus comprising the ink jet head according to claim 11.

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