JP2009297946A - Liquid droplet ejecting head, liquid droplet ejector carrying liquid droplet ejecting head, manufacturing method for liquid droplet ejecting head, and manufacturing method for liquid droplet ejector applying manufacturing method for liquid droplet ejecting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet ejecting head or the like which has a liquid-resistant protective film capable of securing chemical resistance and hydrophilic properties by an inexpensive material. <P>SOLUTION: The liquid droplet ejecting head 10 is equipped with a plurality of nozzle holes 11 which eject liquid droplets, a plurality of ejection chambers 21 communicating with respective nozzle holes 11, a common liquid droplet chamber 23 which is made to communicate with each ejection chamber 21 to supply the liquid to the ejection chamber 21, a diaphragm 6 formed on a wall surface of the ejection chamber 21, and a counter electrode 5 arranged opposite to the diaphragm 6. The liquid droplet ejecting head 10 is comprised of a plurality of stacked substrates 1, 2 and 3. The hydrophilic liquid-resistant protective films 15 and 18 composed of a nitrogen-introduced diamond-like carbon film are formed to surfaces in touch with the liquid of the substrates 1, 2 and 3. The liquid-resistant protective films 15 and 18 may be a single-layer structure or may be a structure of a plurality of layers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, a droplet discharge device equipped with a droplet discharge head, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device to which a method for manufacturing a droplet discharge head is applied.

  As a droplet discharge head, an electrostatic drive type ink jet head mounted on an ink jet recording apparatus is known. In general, the inkjet head includes a nozzle substrate having a plurality of nozzle holes for discharging ink droplets, a discharge chamber connected to the nozzle substrate and communicating with the nozzle holes, a reservoir, and the like. And a cavity substrate on which an ink flow path is formed, and is configured to discharge ink liquid from a selected nozzle hole by applying pressure to the discharge chamber by the driving unit.

  In an ink jet head of a conventional ink jet recording apparatus, an ink-resistant thin film made of titanium is formed on the silicon surface on the discharge chamber side so as not to be corroded by ink. And the titanium surface has hydrophilicity and is formed by sputtering etc. (for example, refer patent document 1).

JP 2004-74809 A (page 4, FIG. 1)

  Since titanium, which is an ink-resistant thin film formed on the silicon surface on the discharge chamber side of the ink jet head described in Patent Document 1, is a rare metal, the price is expected to rise due to the future social situation and may increase the cost. There is.

  The present invention has been made to solve the above-described problems, and a droplet discharge head and a droplet discharge head having a liquid-resistant protective film capable of ensuring chemical resistance and hydrophilicity with inexpensive raw materials. The present invention provides a method for manufacturing a droplet discharge device, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device to which the method for manufacturing a droplet discharge head is applied.

A droplet discharge head according to the present invention includes a plurality of nozzle holes that discharge droplets, a plurality of discharge chambers that communicate with the respective nozzle holes, and a common droplet that communicates with each discharge chamber and supplies liquid to the discharge chamber. A droplet discharge head comprising: a chamber; a diaphragm formed on a wall surface of the discharge chamber; and a counter electrode disposed to face the diaphragm; A hydrophilic liquid-resistant protective film made of a diamond-like carbon film into which nitrogen is introduced is formed on the surface.
A liquid-resistant protective film consisting of a diamond-like carbon film with nitrogen introduced is provided on the surface where the substrate comes into contact with the liquid, so it is a low-cost raw material with excellent hydrophilicity and chemical resistance, and high product reliability. You can get a head.

In the liquid droplet ejection head according to the present invention, the liquid-resistant protective film has a single-layer structure, and is composed of a diamond-like carbon film in which nitrogen is introduced into the entire layer.
A liquid-resistant protective film is formed by a diamond-like carbon film with a single-layer structure into which nitrogen has been introduced, so that a liquid droplet discharge head with excellent hydrophilicity and chemical resistance and high product reliability can be obtained with an inexpensive material. be able to.

The liquid droplet ejection head according to the present invention is a diamond-like carbon film in which the liquid-resistant protective film has a multi-layer structure and nitrogen is introduced into at least the entire surface side layer.
A diamond-like carbon film consists of at least two layers, an inner layer film and an outer layer film. The outer layer film has excellent hydrophilicity and chemical resistance because nitrogen is introduced, and the inner layer film does not have nitrogen introduced, so the deposition rate is A through plot can be raised without lowering.

A droplet discharge apparatus according to the present invention is equipped with the above-described droplet discharge head.
In addition, a droplet discharge device including a droplet discharge head with high product reliability can be obtained.

A method for manufacturing a droplet discharge head according to the present invention includes a plurality of nozzle holes that discharge droplets to a substrate, a plurality of discharge chambers that communicate with the nozzle holes, and a liquid that is connected to the discharge chambers and supplies liquid to the discharge chambers. A method for manufacturing a droplet discharge head, comprising: a common droplet chamber to be supplied; a diaphragm formed on a wall surface of the discharge chamber; and a counter electrode disposed to face the diaphragm; Then, a diamond like carbon film into which nitrogen is introduced is formed on the surface where the substrate comes into contact with the liquid, and the substrates are laminated to manufacture a droplet discharge head.
Since the diamond-like carbon film into which nitrogen is introduced is formed, the water-repellent diamond-like carbon film can be changed in film quality, and a hydrophilic liquid-resistant protective film can be formed at low cost.

A method for manufacturing a droplet discharge device according to the present invention is to apply the above-described method for manufacturing a droplet discharge head to form a droplet discharge head portion of the droplet discharge device.
In addition, a droplet discharge device equipped with a droplet discharge head with high product reliability can be obtained.

Embodiment 1 FIG.
1 is an exploded perspective view showing a part of the inkjet head according to the first embodiment of the present invention in section, FIG. 2 is a longitudinal sectional view showing the main part in the assembled state of FIG. 1, and FIG. It is aa sectional drawing.
The ink jet head 10 is formed in the cavity substrate 2, the nozzle substrate 1 in which a plurality of nozzle holes 11 are provided at a predetermined pitch, the cavity substrate 2 in which an ink supply path is provided independently for each nozzle hole 11, and the cavity substrate 2. The electrode substrate 3 having the individual electrode (counter electrode) 5 facing the vibrating plate 6 is laminated by bonding.

  The nozzle substrate 1 is made of silicon and bonded to the cavity substrate 2. The nozzle hole 11 is a concentrically provided nozzle hole portion formed in a two-stage cylindrical shape having different diameters, that is, a first nozzle hole portion (discharge port portion) 11a having a smaller diameter and a diameter smaller than that. It is composed of a large second nozzle hole portion (introduction port portion) 11b. Further, the nozzle substrate 1 is formed with an orifice 12 that communicates the discharge chamber 21 of the cavity substrate 2 and the reservoir 23, and a diaphragm 13 for compensating for pressure fluctuations in the reservoir 23 portion.

A silicon oxide film (SiO ₂ film) 14 is formed on the surface of the nozzle substrate 1. Further, a diamond-like carbon film (DLC) is further formed on the silicon oxide film 14 on the surface of the nozzle substrate 1 on the nozzle inner wall and the side bonded to the cavity substrate 2, that is, the surface on the ink flow path (liquid flow path) 50 side. An ink protective film (liquid-resistant protective film) 15 is formed. The ink protective film 15 is hydrophilic and has high chemical resistance, and is formed by introducing nitrogen (N ₂ ) during film formation.
The ink protective film 15 may be formed by directly forming the diamond-like carbon film 15 without forming the silicon oxide film 14 on the surface of the nozzle substrate 1 on the ink flow path 50 side.

  The cavity substrate 2 is manufactured from, for example, a silicon substrate having a plane orientation of (110). In the cavity substrate 2, a plurality of discharge chambers 21 that form the ink flow path 50 and one reservoir 23 that is common to each discharge chamber 21 are formed.

  Each discharge chamber 21 is a portion that causes pressure fluctuations to discharge ink from the nozzle hole 11 and communicates with the orifice 12 that is an ink supply port. The bottom surface of the discharge chamber 21 is a diaphragm 6 having flexibility. The diaphragm 6 is formed of a boron diffusion layer in which boron on one surface of the cavity substrate 2 is diffused, and the thickness of the boron diffusion layer is thinned by using an etching stop by wet etching.

  The reservoir 23 is for storing ink, which is a discharge liquid, and communicates with all the discharge chambers 21 via the orifice 12. An ink supply hole 16 communicating with the ink supply hole 33 of the electrode substrate 3 is formed at the bottom of the reservoir 23 so that ink is supplied from an ink cartridge (not shown).

A silicon oxide film (SiO ₂ film) 17 is formed on the surface of the cavity substrate 2 on the side bonded to the nozzle substrate such as the reservoir 23 and the inner wall of the discharge chamber 21, that is, the surface on the ink flow path 50 side. On the silicon oxide film 17, an ink protective film (liquid-resistant protective film) 18 made of a diamond-like carbon film is further formed. The ink protective film 18 is hydrophilic and has high chemical resistance, and is formed by introducing nitrogen during film formation. The ink protective film 18 may be formed by directly forming a diamond-like carbon film without forming the silicon oxide film 17 on the surface of the cavity substrate 2 on the ink flow path 50 side.

An insulating film 8 made of silicon oxide (SiO ₂ ) is formed on the surface of the cavity substrate 2 facing the electrode substrate 3. The insulating film 8 may be made of a so-called high-k material or the like. For example, aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), hafnium nitride silicate (HfSiN), hafnium oxynitride silicate ( A film made of HfSiON) may be used.
Note that a diamond-like carbon film may be further formed on the insulating film 8 as a surface protective film.

  The electrode substrate 3 is produced from a glass substrate. In particular, it is suitable to use Pyrex (registered trademark) glass having a thermal expansion coefficient close to that of the silicon substrate as the cavity substrate 2. This is because when the electrode substrate 3 and the cavity substrate 2 are anodically bonded, since the thermal expansion coefficients of both the substrates are close, the stress generated between the electrode substrate 3 and the cavity substrate 2 can be reduced. This is because the electrode substrate 3 and the cavity substrate 2 can be firmly bonded without causing problems such as peeling.

In the electrode substrate 3, individual electrode forming recesses 32 are respectively formed at the surface positions of the cavity substrate 2 facing the diaphragms 6. In general, ITO (Indium Tin Oxide: indium tin oxide) is formed inside the electrode substrate 3. The individual electrode (counter electrode) 5 is formed.
A diamond-like carbon film may be further formed as a surface protective film on the upper surface of the individual electrode 5 of the electrode substrate 3 or the entire surface on the individual electrode formation side.

The individual electrode 5 has a terminal portion 5a connected to a flexible wiring board (not shown). This terminal portion 5a is provided in an electrode extraction portion 34 in which the end portion of the cavity substrate 2 is opened for wiring. Exposed.
In the individual electrode forming recess 32, the open end of the gap 19 formed between the diaphragm 6 and the individual electrode 5 is sealed with a sealing material 35 made of resin such as epoxy. Thereby, moisture, dust and the like can be prevented from entering the gap 19, and the reliability of the inkjet head 10 can be maintained.

The cavity substrate 2 and the electrode substrate 3 are joined by anodic bonding. When a diamond-like carbon film is provided on the opposing surfaces of the cavity substrate 2 and the electrode substrate 3, they can be bonded by anodic bonding through a silicon oxide film (SiO ₂ film).

A drive control circuit 40 such as a driver IC is connected to the terminal portion 5a of each individual electrode 5 of the electrode substrate 3 and the common electrode 26 on the upper surface of the cavity substrate 2 via a flexible wiring substrate (not shown), and an inkjet A head 10 is configured.
Here, the individual electrode 5 of the electrode substrate 3 and the vibration plate 6 of the cavity substrate 2 constitute an electrostatic actuator that serves to discharge droplets, and the vibration plate 6 constitutes a movable piece of the electrostatic actuator. is doing.

Next, the operation of the inkjet head 10 will be described.
In the inkjet head 10 configured as described above, when a pulse voltage is applied between the common electrode 26 of the cavity substrate 2 and the terminal portion 5a of the electrode substrate 3 by the drive control circuit 40, the diaphragm 6 and the diaphragm 6 are individually separated. An electrostatic force is generated between the electrode 5 and the diaphragm 6 is attracted and bent toward the individual electrode 5 by the suction action, and the volume of the discharge chamber 21 is increased. As a result, the ink accumulated in the reservoir 23 flows into the discharge chamber 21 through the orifice 12. Next, when the application of voltage to the common electrode 26 and the terminal portion 5a is stopped, the electrostatic attractive force disappears, the diaphragm 6 is restored, and the volume of the discharge chamber 21 is rapidly contracted. As a result, the pressure in the discharge chamber 21 rapidly increases, and the ink liquid is discharged from the nozzle holes 11 communicating with the discharge chamber 21.
In this way, the ink accumulated in the reservoir 23 moves in the liquid flow path 50 and is ejected from the nozzle hole 11.
In this way, it is possible to obtain the inkjet head 10 which is an inexpensive raw material, has high ink resistance (chemical resistance), is excellent in stability, and has high product reliability.

Next, the manufacturing method of the inkjet head 10 is demonstrated using the flowchart of FIG. 4, FIG. In addition, the numerical value described below shows an example, and is not limited to this.
First, a method for manufacturing a nozzle substrate will be described with reference to FIG.
A silicon substrate (which becomes the nozzle substrate 1 after processing) is thermally oxidized, and a silicon oxide film (SiO ₂ film) serving as an etching protection film is formed on the surface to a thickness of, for example, 1200 nm (S-1).

  Next, a second recess corresponding to the second nozzle hole portion 11b is formed by patterning in the silicon oxide film and half-etched by wet etching. Next, concentrically with this, a first recess corresponding to the first nozzle hole portion 11a is formed by patterning, and etching is performed by dry etching so that the remaining thickness becomes zero (S-2).

  Next, anisotropic dry etching is performed vertically by ICP (Inductively Coupled Plasma) dry etching to form the first nozzle hole portion 11a, and then the silicon oxide film is wet etched to leave the remaining thickness of the second recess. To be zero. Next, anisotropic dry etching is performed vertically by ICP dry etching to form the second nozzle hole portion 11b. At the same time, the first nozzle hole portion 11a is simultaneously anisotropically dry etched by the same depth. Thus, the nozzle hole 11 composed of the first and second nozzle hole portions 11a and 11b is formed (S-3).

  Next, the silicon oxide film remaining on the surface of the silicon substrate is peeled off (S-4).

Next, a silicon oxide film (SiO ₂ film) 14 is formed on the surface of the silicon substrate (S-5). The silicon oxide film 14 is formed on both surfaces of the silicon substrate by thermal oxidation or a CVD apparatus. Note that the film can be formed only on the surface on the liquid discharge side, and in this case, the film is formed by a CVD apparatus.

Next, a diamond-like carbon film is further formed on the silicon oxide film 14 on the nozzle inner wall of the silicon substrate and the surface that is bonded to the cavity substrate 2, that is, the surface that becomes the ink flow path 50 (see FIG. S-6). A plasma CVD apparatus is used as the film formation apparatus, and toluene (C ₇ H ₈ ) is used as the source gas. In addition to toluene (C ₇ H ₈ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), acetylene (C ₂ H ₂ ) , Benzene (C ₆ H ₆ ) and the like can be used.
In this case, a diamond-like carbon film is formed with a high frequency output of 900 W, a toluene flow rate of 5 sccm, a pressure of 0.2 Pa, and a nitrogen flow rate of 5 sccm. In this case, it takes about 60 minutes to form a diamond-like carbon film having a thickness of 0.1 μm.
Here, the thickness of the diamond-like carbon film is 0.1 μm, but the film thickness is set according to the durability of the ink protective film (ink resistance) with the ink used.
The above conditions are merely examples, and various conditions are arbitrarily set according to the application (guaranteed range, film formation rate improvement).

  Since the diamond-like carbon film formed as described above is formed by introducing nitrogen, the pure water contact angle is about 40 °. When nitrogen is not introduced into the diamond-like carbon film, the pure water contact angle is about 80 °. A diamond-like carbon film is generally a film having water repellency, but it can be seen that a film having hydrophilicity can be obtained by introducing nitrogen as described above.

Next, water repellent treatment is performed on the surface of the silicon substrate on the liquid discharge side (S-7).
Thus, the nozzle substrate 1 is completed from the silicon substrate (S-8).

Next, the manufacturing method of the electrode substrate 3 and the cavity substrate 2 is demonstrated using FIG.
First, a glass substrate made of Pyrex (registered trademark) glass (becomes an electrode substrate 2 after processing) is etched with hydrofluoric acid using, for example, an etching mask made of gold and chrome, for forming individual electrodes having a desired depth. A recess 32 is formed (S-9). The individual electrode forming recess 32 has a groove shape slightly larger than the shape of the individual electrode 5, and a plurality of recesses 32 are formed for each individual electrode 5. Then, for example, an ITO film is formed by sputtering. Further, the ITO film is patterned by photolithography, and the individual electrode 5 is formed by etching or the like leaving the ITO only in the individual electrode forming recess 32 (S-10).
Next, a hole is made in the glass substrate with a drill or the like to form the ink supply hole 33.
Thus, the electrode substrate 3 is completed from the glass substrate (S-11).

Further, a boron diffusion layer is formed on the entire surface of one side of a silicon substrate (which will be the cavity substrate 2 after processing), and further, an insulation made of a silicon oxide film (SiO ₂ film) is formed on the entire surface of the boron diffusion layer by CVD or the like. The film 8 is formed (S-12).

  Next, the silicon substrate processed as described above and the electrode substrate 3 are bonded and laminated. This is because the region where the diaphragm 6 of the silicon substrate is to be formed and the individual electrode 5 of the individual electrode forming recess 32 of the electrode substrate 3 are opposed to each other with a gap 19 between them. The part in the contact is brought into close contact and anodic bonding is carried out (S-13).

  Next, the entire surface of the bonded silicon substrate is polished and thinned, and light etching is further performed by wet etching to remove the processing trace (S-14).

  Next, resist patterning is performed on the surface of the bonded silicon substrate processed into a thin plate shape by photolithography (S-15), and grooves serving as ink flow paths are formed by etching (S-16). As a result, a recess serving as the discharge chamber 21, a recess serving as the reservoir 23, and a recess serving as the electrode extraction portion 34 are formed. At this time, for example, if wet etching is performed with potassium hydroxide, the etching is stopped on the surface of the boron diffusion layer, so that the thickness of the diaphragm 6 can be formed with high accuracy and surface roughness can be prevented.

  Next, the bottom of the recess corresponding to the electrode lead-out portion 34 is removed by ICP (Inductively Coupled Plasma) dry etching to open the electrode lead-out portion 34.

  Next, the moisture adhering to the inside is removed from the gap (gap in the actuator) 19 between the individual electrode 5 and the diaphragm 6 formed in the individual electrode forming recess 32 (S-17). Moisture removal is performed by placing the laminated silicon substrate in, for example, a vacuum chamber and evacuating with heat. Then, after the required time has elapsed, nitrogen gas is introduced, and a sealing material 35 such as an epoxy resin is applied to the open end of the gap 19 in a nitrogen atmosphere to seal it hermetically (S-18). In this way, after removing the water adhering to the gap 19, the driving durability of the electrostatic actuator is improved by hermetically sealing.

Next, a silicon substrate is formed on the surface on the adhesion side with the nozzle substrate 1, such as a recess serving as the discharge chamber 21 of the silicon substrate, a recess serving as the reservoir 23, and a recess serving as the electrode extraction portion 34, that is, the surface on the ink flow path 50 side. An oxide film (SiO ₂ film) 17 is formed (S-19). Then, an ink protective film 18 made of a diamond-like carbon film is further formed on the silicon oxide film 17 (S-20).

In this case, the ink protective film 18 is formed by the same method as that for forming a diamond-like carbon film on the surface of the silicon substrate (nozzle substrate 1) on the ink flow path 50 side (S-6 in FIG. 4). That is, a plasma CVD apparatus is used as the film forming apparatus, and for example, toluene (C ₇ H ₈ ) is used as the source gas. A diamond-like carbon film is formed with a high frequency output of 900 W, a toluene flow rate of 5 sccm, a pressure of 0.2 Pa, and a nitrogen flow rate of 5 sccm. In this case, it takes about 60 minutes to form a diamond-like carbon film having a thickness of 0.1 μm.
Here, the thickness of the diamond-like carbon film is 0.1 μm, but the thickness of the diamond-like carbon film is set according to the durability of the ink protective film (ink resistance) with the ink used.
Since the diamond-like carbon film configured as described above is formed by introducing nitrogen, the contact angle of pure water is about 40 °, and it can be seen that a film having hydrophilicity is obtained by introducing nitrogen. .
Next, a common electrode 26 made of metal is formed on the silicon substrate.

  Through the above steps, the cavity substrate 2 is completed from the silicon substrate bonded to the electrode substrate 3 (S-21).

Next, the nozzle substrate 1 manufactured in S-8 (see FIG. 4) is bonded to the surface of the cavity substrate 2 by bonding, thereby completing the bonded substrate (S-22).
Finally, the ink jet head 10 is completed by cutting into individual head chips by dicing (S-23).

  Thus, since the ink protective films 15 and 18 made of a diamond-like carbon film having a film quality changed by introducing nitrogen are formed on the surface of the ink flow path 50 of the inkjet head 10, the ink contact surface of the ink flow path 50 is hydrophilic. And has high chemical resistance.

Embodiment 2. FIG.
FIG. 6 is a cross-sectional view of the second embodiment showing a state where the inkjet head of FIG. 2 is cut along the aa line.
In the first embodiment, the ink protective films 15 and 18 provided on the surface of the ink flow path 50 of the ink jet head 10 are each formed of a single-layer diamond-like carbon film. In the second embodiment, a two-layer diamond is used. It is formed by a like carbon film and the upper layer portion is made hydrophilic.

As shown in FIG. 6, a silicon oxide film (SiO ₂ film) 14 is formed on the surface of the nozzle substrate 1. An ink protective film 15 made of a diamond-like carbon film is formed on the silicon oxide film 14 on the nozzle inner wall of the nozzle substrate 1 and the surface on the cavity substrate 2 side, that is, the surface on the ink flow path 50 side. Yes. This ink protective film 15 has a two-layer structure, and is composed of an inner layer film 15a and an outer layer film 15b formed thereon, and the outer layer film 15b is composed of a hydrophilic diamond-like carbon film into which nitrogen is introduced during film formation. The inner layer film 15a is made of a diamond-like carbon film into which nitrogen is not introduced.

Further, a silicon oxide film (SiO ₂ film) 17 is formed on the surface of the cavity substrate 2 such as the reservoir 23 and the inner wall of the discharge chamber 21 on the nozzle substrate 1 side, that is, the surface on the ink flow path 50 side. An ink protective film 18 made of a diamond-like carbon film is further formed on the silicon oxide film 17. The ink protective film 18 has a two-layer structure, and is composed of an inner layer film 18a and an outer layer film 18b formed thereon, and the outer layer film 18b is composed of a hydrophilic diamond-like carbon film into which nitrogen is introduced during film formation. The inner layer film 18a is made of a diamond-like carbon film into which nitrogen is not introduced.
Other configurations and effects are the same as in the case shown in the first embodiment, and a description thereof will be omitted.

Next, a method for manufacturing the inkjet head 10 will be described.
The manufacturing method of the ink jet head 10 according to the second embodiment is substantially the same as the manufacturing method shown in the first embodiment, but in the manufacturing process of the nozzle substrate 1 and the cavity substrate 2, ink protection on the nozzle substrate 1 side is performed. The step of forming the film 15 (see S-6 in FIG. 4) is different from the step of forming the ink protective film 18 on the cavity substrate 2 side (see S-20 in FIG. 5).
Hereinafter, the difference will be described.

A diamond-like carbon film 15 is formed on the silicon oxide film (SiO ₂ film) 14 formed on the surface of the silicon substrate (nozzle substrate 1) and on the surface that becomes the ink flow path 50. At this time, unlike S-6 in FIG. 4 of the first embodiment, the diamond-like carbon film 15 is formed in two layers.
A plasma CVD apparatus is used as the film formation apparatus, and toluene (C ₇ H ₈ ) is used as the source gas. In addition to toluene (C ₇ H ₈ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), acetylene (C ₂ H ₂ ) , Benzene (C ₆ H ₆ ) and the like can be used.
The diamond-like carbon film inner layer film 15a is formed at a high frequency output of 900 W, a toluene flow rate of 5 sccm, and a pressure of 0.2 Pa. At this time, nitrogen is not introduced. Thus, it takes about 10 minutes to form the inner layer film 15a to 0.08 μm.

Next, the outer layer film 15b of the diamond-like carbon film is formed with a high frequency output of 900 W, a toluene flow rate of 5 sccm, a pressure of 0.2 Pa, and a nitrogen flow rate of 5 sccm. Nitrogen is not introduced when forming the inner layer film 15a, but nitrogen is introduced as described above when forming the outer layer film 15b. It takes about 12 minutes to form 0.02 μm of the outer layer film 15b.
Thus, it takes about 22 minutes in total to form the inner layer film 15a and the outer layer film 15b of the diamond-like carbon film.

Similarly, on the silicon oxide film (SiO ₂ film) 17 formed on the surface of the silicon substrate (cavity substrate 2) that becomes the ink flow path 50, the inner layer film 18a and the inner layer film 18a are formed by the same method as described above. A diamond-like carbon film composed of the outer layer film 18b is formed. It differs from S-20 of Embodiment 1 (see FIG. 4) in that a diamond-like carbon film is formed in two layers. The manufacturing method is the same as that for forming the diamond-like carbon film inner layer film 15a and outer layer film 15b on the silicon substrate (nozzle substrate 1), and the description thereof will be omitted.

The ink protective films 15 and 18 are formed as described above. However, when nitrogen is introduced when the diamond-like carbon film is formed, the film formation rate decreases. Therefore, in order to increase the through plot, it is effective to form a diamond-like carbon film by introducing nitrogen after forming a diamond-like carbon film without introducing nitrogen.
Therefore, in the second embodiment, when forming the diamond-like carbon film, first, the inner layer films 15a and 18a are formed without introducing nitrogen, and then nitrogen is formed on the inner layer films 15a and 18a. The introduced outer layer films 15b and 18b are formed.
Other manufacturing steps and effects are the same as those in the case of the first embodiment, and thus description thereof is omitted.

  In the above description, the case where the diamond-like carbon film constituting the ink protective films 15 and 18 is two layers is shown, but it may be composed of three layers, four layers or more layers. The outer layer film located on the outermost surface is made hydrophilic by introducing nitrogen.

The ink jet head and the manufacturing method thereof described in the first and second embodiments are examples, and various other methods can be applied outside the scope of the technical idea of the present invention.
In the first and second embodiments, the case where the electrostatic actuator of the present invention is applied to an inkjet head for ejecting liquid droplets has been described. However, the electrostatic actuator is not limited thereto, and an optical switch, a mirror device, It can also be used for a driving part of a laser pump or a laser operation mirror of a laser printer.
Furthermore, as an inkjet head, by changing the type of liquid ejected from the nozzle holes, in addition to the inkjet printer as shown in FIG. 7, the manufacture of color filters for liquid crystal displays and the formation of light emitting portions of organic EL display devices It can also be used in a droplet discharge portion of a droplet discharge device for various uses such as manufacturing a microarray of a biomolecule solution used for genetic testing or the like.

FIG. 2 is an exploded perspective view showing a part of the inkjet head according to the first embodiment of the present invention in cross section. The longitudinal cross-sectional view which shows the principal part of the assembled state of the inkjet of FIG. FIG. 3 is a cross-sectional view of the inkjet head of FIG. 3 is a flowchart showing a method for manufacturing the ink jet head according to the first embodiment. 3 is a flowchart showing a method for manufacturing the ink jet head according to the first embodiment. Sectional drawing of the inkjet head which concerns on Embodiment 2 of this invention. 1 is a perspective view of an ink jet printer including an electrostatic actuator according to the present invention.

Explanation of symbols

  1 nozzle substrate (silicon substrate), 2 cavity substrate (silicon substrate), 3 electrode substrate (glass substrate), 5 individual electrode (counter electrode), 6 diaphragm, 8 insulating film, 10 inkjet head (droplet ejection head), DESCRIPTION OF SYMBOLS 11 Nozzle hole, 12 Orifice, 13 Diaphragm, 14, 17 Silicon oxide film, 15, 18 Ink protective film (liquid-resistant protective film, diamond-like carbon film), 15a, 18a Inner layer film, 15b, 18b Outer layer film, 19 Gap, 21 discharge chamber, 23 reservoir (common droplet chamber), 26 common electrode, 32 individual electrode forming recess, 16, 33 ink supply hole, 34 electrode takeout portion, 35 sealing material, 40 drive control circuit, 50 liquid flow path .

Claims (6)

A plurality of nozzle holes for discharging droplets, a plurality of discharge chambers communicating with the respective nozzle holes, a common droplet chamber communicating with each of the discharge chambers and supplying liquid to the discharge chambers, A droplet discharge head comprising a diaphragm formed on a wall surface and a counter electrode disposed opposite to the diaphragm, and a plurality of substrates laminated,
A droplet discharge head, wherein a hydrophilic liquid-resistant protective film made of a diamond-like carbon film into which nitrogen is introduced is formed on a surface of the substrate that comes into contact with a liquid.   2. The liquid droplet ejection head according to claim 1, wherein the liquid-resistant protective film has a single-layer structure and is composed of a diamond-like carbon film in which nitrogen is introduced to the entire layer.   2. The liquid droplet ejection head according to claim 1, wherein the liquid-resistant protective film has a multi-layer structure and is composed of a diamond-like carbon film in which nitrogen is introduced into at least the entire surface side layer.   A droplet discharge apparatus comprising the droplet discharge head according to claim 1. A plurality of nozzle holes for discharging droplets to the substrate; a plurality of discharge chambers communicating with the respective nozzle holes; a common droplet chamber communicating with each of the discharge chambers and supplying a liquid to the discharge chamber; A method for manufacturing a droplet discharge head, comprising: a diaphragm formed on a wall surface of a discharge chamber; and a counter electrode disposed opposite to the diaphragm, and a plurality of substrates stacked.
A method of manufacturing a droplet discharge head, comprising: forming a diamond-like carbon film into which nitrogen is introduced on a surface of the substrate in contact with a liquid; and stacking the substrates to manufacture a droplet discharge head.   6. A method for manufacturing a droplet discharge device, comprising applying the method for manufacturing a droplet discharge head according to claim 5 to form a droplet discharge head portion of the droplet discharge device.

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