JP2007336660A - Methods of manufacturing electrostatic actuator, liquid droplet discharging head and liquid droplet discharging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrostatic actuator by which an electrostatic actuator having high discharging characteristics and drive durability can be manufactured by suppressing the deposition of metallic impurities, and to provide methods of manufacturing a liquid droplet discharging head and a liquid droplet discharging device. <P>SOLUTION: The method has a step of forming a boron dope layer on one surface of a Si substrate 41 using boron diffusion sources 51 and in which the boron dope layer is formed as a vibrating plate by an etching stop technology. The boron diffusion source that has B<SB>2</SB>O<SB>3</SB>as a main component and Rh content of ≤0.44 ppm is used as the boron diffusion source 51 when the boron dope layer is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electrostatic actuator, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device, which are used as a drive mechanism for an inkjet head or the like.

  As a droplet discharge method for a printer or the like, a discharge chamber (also referred to as a pressure chamber) that stores discharge liquid is provided in a part of the flow path, and at least one wall of the discharge chamber (here, a bottom wall, hereinafter, There is a method in which a droplet is discharged from a communicating nozzle by increasing the pressure in the discharge chamber by bending and displacing the wall (hereinafter referred to as a diaphragm). In this case, as a force for displacing the diaphragm serving as the movable electrode, the diaphragm and the counter electrode (fixed electrode) are opposed to each other through a gap to constitute an actuator, and static electricity generated by applying a voltage between them. One that uses force is widely known.

  The electrostatic actuator as described above or a droplet discharge head using the electrostatic actuator is required to stabilize discharge characteristics and driving durability, and the following two proposals are proposed as manufacturing processes for realizing the requirements. Has been.

  One is a process for forming a diaphragm with high precision on a silicon substrate using an etching stop technique based on boron diffusion. The other is a process for hydrophobizing the actuator using HMDS (hexamethyldisilazane). In this process, a hydrophobic film is formed on each electrode part (common electrode part, fixed electrode part) to form a diaphragm having high driving durability.

  As a method of diffusing boron in the silicon substrate in the first diaphragm formation process, a method using a liquid boron diffusion source (see, for example, Patent Document 1) or a method using a solid boron diffusion source ( For example, see Patent Document 2).

JP 2004-82572 A JP 2004-306444 A

After performing boron diffusion on the silicon substrate using the conventional boron diffusion method described above, a diaphragm is formed by etching a predetermined portion. Prior to the etching, the SiO ₂ film serving as an etching mask is formed on the surface of the silicon substrate. It is formed by thermal oxidation. Further, as a final form of the cavity substrate, a SiO ₂ film is formed on the surface of the silicon substrate by thermal oxidation on the ink protective film in the ink flow path portion and the insulating film on the actuator side. Since the temperature of thermal oxidation at the time of forming the SiO ₂ film is as high as 1000 ° C. or more, metal impurities contained in the boron diffusion source at the time of boron diffusion, for example, Rh (rhodium), diffused in the silicon substrate Precipitates on the substrate surface (on the boron diffusion surface side), and there is a problem that Si crystal defects occur.

When metal impurities are deposited on the substrate surface in this way, when the SiO ₂ film to be an insulating film is formed, the metal impurities obstruct oxidation and the portion of the SiO ₂ film (insulating film) is formed thinly. The dielectric breakdown voltage of the Si crystal defect portion (metal impurity precipitation portion) is lowered, and discharge is generated starting from that portion during driving. As a result, the hydrophobized film made of HMDS formed in the actuator and the gap between the floating substances in the gap (unreacted HMDS, NH ₃ , intermediate products) are broken, and a polymerized substance is generated and grows in the actuator. There is a problem in that this polymerized material is laminated in the actuator to obstruct the operation of the diaphragm, and the discharge characteristics and driving durability are remarkably lowered.

  The present invention has been made in view of the above problems, and an electrostatic actuator manufacturing method capable of manufacturing an electrostatic actuator having high ejection characteristics and high drive durability by suppressing deposition of metal impurities, and a droplet ejection head. It is an object to provide a manufacturing method and a manufacturing method of a droplet discharge device.

An electrostatic actuator manufacturing method according to the present invention includes a step of forming a boron doped layer on one surface of a Si substrate using a boron diffusion source, and forming the boron doped layer as a diaphragm by an etching stop technique. In this manufacturing method, a boron diffusion source containing B ₂ O ₃ as a main component and having an Rh content of 0.44 ppm or less is used as the boron diffusion source when forming the boron doped layer.

The electrostatic actuator manufacturing method according to the present invention further includes a step of forming a boron doped layer on one surface of the Si substrate using a boron diffusion source, and forming the boron doped layer as a diaphragm by an etching stop technique. In the method for manufacturing an electric actuator, a boron diffusion source when forming a boron doped layer is mainly composed of B ₂ O ₃ , Ni content: 2.0 ppm or less, Cu content: 0.5 ppm or less, Rh content: A boron diffusion source having 0.44 ppm or less, Fe content: 2.0 ppm or less, Cr content: 2.0 ppm or less, and Zn content: 2.0 ppm or less is used.

By forming a boron-doped layer using the above boron diffusion source, the generation of Si crystal defects is suppressed (suppression of the dielectric breakdown voltage of the SiO ₂ film (insulating film) in the Si crystal defect portion), and the charge during operation of the diaphragm Movement (discharge) can be suppressed, and an electrostatic actuator having stable diaphragm operating characteristics and driving durability (reliability) can be obtained.

A method of manufacturing an electrostatic actuator according to the present invention has a step of forming a SiO ₂ film on the Si substrate after the boron diffusion, the SiO ₂ film forming step, a SiO ₂ film by a low-temperature film formation by CVD or sputtering To form.
By adopting the thermal oxidation process at a low temperature in this way, metal impurity precipitation itself can be suppressed, and further quality stabilization can be achieved.

A method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head by applying any of the above-described methods for manufacturing an electrostatic actuator.
Thereby, a droplet discharge head having stable discharge characteristics and driving durability (reliability) can be obtained.

A method for manufacturing a droplet discharge device according to the present invention is a method for manufacturing a droplet discharge device by applying the method for manufacturing a droplet discharge head described above.
Thereby, a droplet discharge device having stable discharge characteristics and driving durability (reliability) can be obtained.

  Hereinafter, embodiments of a droplet discharge head including an electrostatic actuator according to the present invention will be described with reference to the drawings. Here, as an example of a droplet discharge head, a face discharge type inkjet head that discharges ink droplets from ink nozzles provided on the surface of a nozzle substrate will be described with reference to FIGS. The present invention is not limited to the structure and shape shown in the following drawings, and can also be applied to an edge discharge type inkjet head that discharges ink droplets from ink nozzles provided at the end of a substrate. It is.

Embodiment 1 FIG.
FIG. 1 is an exploded perspective view showing an exploded schematic configuration of the ink jet head according to the first embodiment, and a part thereof is shown in cross section. FIG. 2 is a cross-sectional view of the ink jet head showing a schematic configuration in an assembled state. FIG. 3 is an enlarged cross-sectional view in the width direction of the electrostatic actuator portion in the ink jet head. 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 the first embodiment includes a nozzle substrate 1 provided with a plurality of ink nozzles (nozzle holes) 11 at a predetermined pitch. The cavity substrate 2 provided with an ink supply path independently for each ink nozzle 11 and the electrode substrate 3 provided with the individual electrodes 31 facing the vibration plate 22 of the cavity substrate 2 are bonded together. It is configured.

The electrostatic actuator according to the first embodiment includes the diaphragm 22 as one opposing member that can be elastically deformed, and an SiO ₂ film (insulating film) 26a and a certain gap (gap) G in the diaphragm 22. 2 and the above-mentioned individual electrode 31 that is the other opposing member, and a drive control circuit 4 that applies a drive voltage between the individual electrode 31 and the diaphragm 22 to generate an electrostatic force, and further includes FIG. As shown in FIG. 3, a hydrophobic film 29 made of hexamethyldisilazane (HMDS) is formed on the surface of the SiO ₂ film (insulating film) 26 a formed on the lower surface of the diaphragm 22 and the surface of the individual electrode 31. Is formed.
Hereinafter, the configuration of each substrate constituting the inkjet head 10 will be described.

The nozzle substrate 1 is made of, for example, a silicon substrate having a thickness of 100 μm, and a plurality of ink nozzles 11 are formed. As shown in FIG. 2, each ink nozzle 11 has a cylindrical ejection port portion 11a perpendicular to the surface of the nozzle substrate 1, and is provided coaxially with the ejection port portion 11a and has a diameter larger than that of the ejection port portion 11a. An inlet part 11b having a large (or cross-sectional area) is provided. Thus, by making the ink nozzle 11 have a two-stage hole, the ink droplet ejection direction can be aligned with the central axis direction of the ink nozzle 11, and stable ink ejection characteristics can be exhibited. . That is, there is no variation in the flying direction of the ink droplets, there is no scattering of the ink droplets, and variations in the ejection amount of the ink droplets can be suppressed.
Further, in FIG. 2 of the nozzle substrate 1, a narrow groove-like orifice 13 that forms a part of the ink flow path is provided on the lower surface (the surface on the bonding side with the cavity substrate 2).

  The cavity substrate 2 is made of, for example, a Si substrate having a thickness of 180 μm. By performing anisotropic wet etching on the silicon substrate, recesses 24 and 25 for forming the ink chamber (discharge chamber) 21 and the reservoir 23 of the ink flow path are formed. A plurality of recesses 24 are independently formed at positions corresponding to the ink nozzles 11. Therefore, when the nozzle substrate 1 and the cavity substrate 2 are joined as shown in FIG. 2, each concave portion 24 constitutes an ink chamber 21 and communicates with the ink nozzle 11 respectively, and the orifice 13 serving as an ink supply port. Both communicate with each other. The bottom wall of the ink chamber 21 (recess 24) serves as the diaphragm 22. The diaphragm 22 is composed of a boron-doped layer formed by diffusing high-concentration boron with a required thickness on a silicon substrate. By configuring the diaphragm 22 with a boron-doped layer, etching stop sufficiently works on the surface of the boron-doped layer, so that the surface roughness of the diaphragm 22 can be suppressed and the thickness thereof can be processed with high accuracy. Here, the present invention is characterized by the diffusion source used when forming the boron-doped layer, and details thereof will be described later.

  The other concave portion 25 is for storing liquid material ink, and constitutes a common reservoir (common ink chamber) 23 for each ink chamber 21. The reservoirs 23 (recesses 25) communicate with all the ink chambers 21 through the orifices 13, respectively. Further, a hole penetrating the electrode substrate 3 described later is provided in the bottom of the reservoir 23, and ink is supplied from an ink cartridge (not shown) through the ink supply hole 34 of the hole.

An SiO ₂ film (insulating film) 26a having a thickness of 0.1 μm is applied to the entire surface of the cavity substrate 2 or at least the surface facing the electrode substrate 3 by thermal oxidation, CVD (Chemical Vapor Deposition), or sputtering. The SiO ₂ film (insulating film) 26a is provided for the purpose of preventing dielectric breakdown and short circuit when the ink jet head is driven. Further, a hydrophobic film 29 is formed on the surface of the SiO ₂ film (insulating film) 26a.
On the upper surface of the cavity substrate 2, that is, the surface facing the nozzle substrate 1 (including the inner surfaces of the ink chamber 21 and the reservoir 23), an SiO ₂ film (ink protective film) 26b is formed. This SiO ₂ film (ink protective film) 26b is provided to prevent corrosion of the flow path by ink.

  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 substrate 2. This is because when the electrode substrate 3 and the cavity substrate 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 substrate 2 can be reduced. This is because the electrode substrate 3 and the cavity substrate 2 can be firmly bonded without causing the above problem. The electrode substrate 3 may be a silicon substrate made of the same material as the cavity substrate 2.

The electrode substrate 3 is provided with a recess 32 at a position on the surface of the cavity substrate 2 facing each diaphragm 22. The recess 32 is formed to a depth of about 0.2 μm by etching. And in each recessed part 32, the individual electrode 31 which consists of ITO (Indium Tin Oxide: Indium tin oxide), for example is formed by the thickness of 0.1 micrometer, for example. The open end of the gap G is hermetically sealed with a sealing material 27 made of, for example, SiO ₂ or an epoxy adhesive. Thereby, moisture, dust, etc. can be prevented from entering the gap, and the reliability of the inkjet head 10 can be kept high. A hydrophobic film 29 made of HMDS is also formed on the surface of the individual electrode 31 (see FIGS. 2 and 3).

  The individual electrode 31 has a lead part 31a and a terminal part 31b connected to a flexible wiring board (not shown). The terminal portion 31b is exposed in the electrode extraction portion 35 in which the rear end portion of the cavity substrate 2 is opened in order to facilitate connection of the flexible wiring board.

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, 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 ink chamber 21 increases. When the supply of electric charges to the individual electrodes 31 is stopped, the diaphragm 22 returns to its original state due to its elastic force, and at this time, the volume of the ink chamber 21 is rapidly reduced. Part of the ink is ejected from the ink nozzle 11 as ink droplets. Next, when the vibration plate 22 is similarly displaced, ink is supplied from the reservoir 23 through the orifice 13 into the ink chamber 21.
The ink used in the inkjet head 10 is prepared by dissolving or dispersing a surfactant such as ethylene glycol and a dye or pigment in a main solvent such as water or alcohol.

Next, a manufacturing process of the droplet discharge head including the electrostatic actuator according to the first embodiment will be described with reference to FIGS. 4 is a manufacturing process diagram of a cavity substrate, FIG. 5 is a boron diffusion method diagram, and FIG. 6 is a manufacturing process diagram of a droplet discharge head following FIG. Here, a case where a 2 μm diaphragm is formed using a boron diffusion source mainly composed of B ₂ O ₃ will be described in detail.
(A) First, both surfaces (Cav surface 41a, Dope surface 41b) of the Si substrate 41 having a plane orientation of (110) are mirror-polished to produce a substrate having a thickness of 180 μm.
(B) The Si substrate 41 is set in a thermal oxidation furnace, subjected to thermal oxidation treatment at 1100 ° C. for 4 hours in an oxygen and water vapor atmosphere, and an oxide film (SiO _{2) is formed on} the Cav surface 41a and the Dope surface 41b of the Si substrate 41. ) 42 is formed to a thickness of 1.2 μm.
(C) Next, in order to remove the oxide film 42 on the Dope surface 41b forming the boron doped layer, a resist is coated on the Cav surface 41a of the Si substrate 41, and using the resist as a protective film, the oxide film 42 on the Dope surface 41b is hydrofluoric acid. Etching is removed with an aqueous solution, and the resist is removed after etching.

(D) Next, boron is doped into the Dope surface 41b on which the boron doped layer of the Si substrate 41 is formed. That is, as shown in FIG. 5, a solid diffusion source 51 is set on a quartz boat 54 so as to overlap with a support substrate 52 made of SiC, and is separated from the diffusion source 51 by 2.5 mm, and the Dope surface 41b and the diffusion source 51 are separated. Set with facing each other. A dummy silicon substrate 53 is set above the Si substrate 41 in order to prevent boron from entering. A quartz boat 54 is set in a vertical furnace, the inside of the furnace is put into a nitrogen atmosphere, the temperature is raised to 1100 ° C., the temperature is maintained for 6 hours, and boron is diffused into the Si substrate 41 to form a boron doped layer 43. To do.

A boron compound is formed on the Dope surface 41b of the Si substrate 41 of the boron doped layer 43 (not shown). By oxidizing in an oxygen and water vapor atmosphere at 600 ° C. for 1 hour and 30 minutes, an aqueous hydrofluoric acid solution is used. It can be chemically changed to B ₂ O ₃ + SiO ₂ which can be etched. In a state where it is chemically changed to B ₂ O ₃ + SiO ₂ , a resist is coated on the Cav surface 41a, and B ₂ O ₃ + SiO ₂ is removed by etching with a hydrofluoric acid solution using the resist as a protective film. After etching, the resist is peeled off. To do.

Here, in the present invention, the diffusion source 51 with a limited metal impurity content is used for the purpose of preventing metal impurities from being deposited on the surface (Dope surface 41b) of the Si substrate 41. Specifically, the main component is B ₂ O ₃ , and the metal impurity content is Ni content: 2.0 ppm or less, Cu content: 0.5 ppm or less, Rh content: 0.44 ppm or less, Fe content: 2 A solid diffusion source specified as 0.0 ppm or less, Cr content: 2.0 ppm or less, and Zn content: 2.0 ppm or less is used. By using such a diffusion source 51, it is possible to prevent deposition of metal impurities even when a high-temperature thermal process (step (e) and step (i) described later) is performed later.

(E) Next, the Si substrate 41 is set in a thermal oxidation furnace to be in an oxygen and water vapor atmosphere, subjected to thermal oxidation treatment at a temperature of 1100 ° C. for 4 hours, and a 1.2 μm SiO ₂ film on the surface of the Si substrate 41 44 is formed.
(F) Then, a resist is coated on both surfaces of the Si substrate 41, and a resist 45 for forming a discharge chamber or the like is patterned on the Cav surface 41a side.
(G) The Cav surface 41a patterned with the resist 45 is etched with a hydrofluoric acid aqueous solution to pattern the SiO ₂ film 44, and then the resist 45 on both surfaces of the Si substrate 41 is peeled off. As a result, the resist-coated portion of the SiO ₂ film 44 remains and becomes a mask pattern for the next etching step (h).
(H) The Si substrate 41 having the mask pattern is immersed in a 35 wt% high-concentration potassium hydroxide aqueous solution, Si etching is performed, and etching is continued until the etching portion Si thickness becomes 10 μm. Thereafter, Si etching is performed by immersing the Si substrate 41 in a 3 wt% low-concentration potassium hydroxide aqueous solution. When reaching the boron doped layer 43, the etching is stopped and the boron doped layer 43 remains. The boron doped layer 43 has a thickness of 2 μm and becomes the diaphragm 22.
(I) Then, a SiO ₂ film 44 remaining on the Si substrate 41 was removed by etching with hydrofluoric acid aqueous solution, then, thermal oxidation on the surface of the Si substrate 41 (Celsius 1000 ° C., 5 hours) by, 0.1 [mu] m SiO ₂ A film (insulating film) 26a and a SiO ₂ film (ink protective film) 26b are formed.
Through the above steps, the cavity substrate 2 is formed.

(J) The cavity substrate 2 is anodic bonded to the electrode substrate 3 and the cavity substrate 2 in which the recess 32 is provided at a position facing the diaphragm 22 in the borosilicate glass substrate, and the individual electrode 31 made of ITO is formed on the bottom surface of the recess 32. Thereafter, the inside of the electrostatic actuator is subjected to HMDS treatment and sealing by a conventionally known method as disclosed in, for example, Japanese Patent Laid-Open No. 11-115189, and the hydrophobic film 29 is formed.
(K) Thereafter, the nozzle substrate 1 formed with nozzle holes or the like is bonded onto the cavity substrate 2 with an adhesive or the like, and cut into head chips.

Here, in the present invention, when the boron doped layer 43 is formed, as described above, B ₂ O ₃ is the main component and the metal impurity content is defined (Ni content: 2.0 ppm or less, Cu content: 0.5 ppm or less, Rh content: 0.44 ppm or less, Fe content: 2.0 ppm or less, Cr content: 2.0 ppm or less, Zn content: 2.0 ppm or less) Solid diffusion source 51 (4 inches, 2 mm thick) is used. Using the solid diffusion source 51 in which only the Rh content is changed at the specified metal impurity content, the patterning thermal oxide film forming step (e) and the insulating film by thermal oxidation (i) above The formation process was carried out, and an experiment was conducted to evaluate whether or not a Si crystal defect due to metal impurity precipitation and the occurrence of diaphragm operation inhibition due to the generation of a polymerized substance were generated. The number of evaluation wafers at each experimental level was n = 13, and the results are shown in FIG. When the Rh content was 0.44 ppm or less (experimental levels (1), (2), (3)), it was confirmed that Si crystal defects due to metal impurity precipitation and diaphragm operation inhibition due to the generation of polymer substances did not occur. As described above, in the case of a silicon substrate in which no metal impurities are precipitated and there is no Si crystal defect, the problem of lowering the dielectric strength of the SiO ₂ film (insulating film) in the Si crystal defect portion does not occur. It is possible to prevent the movement (discharge) of charges at the time of separation. Therefore, it is possible to prevent the formation and growth of the polymerized material by breaking the bond between the hydrophobized film 29 made of HMDS and the floating material in the gap (unreacted HMDS, NH ₃ , intermediate product). Problems such as obstruction of diaphragm operation by substances can be avoided. Further, in the discharge capability inspection of the droplet discharge head manufactured using the cavity substrate 2 in which the boron doped layer 43 was formed using the diffusion source 51, normal discharge was confirmed.

  On the other hand, when the Rh content is 0.90 ppm or more (experimental levels (4) and (5)), it is caused by Si crystal defects and generation of polymer substances due to metal impurity precipitation (here, Rh is precipitated). Occurrence of diaphragm operation obstruction was confirmed, and it was confirmed that normal ejection could not be performed in the ejection capacity test.

As described above, according to the first embodiment, the generation of Si crystal defects is suppressed by limiting the metal impurity content in the boron diffusion source (SiO ₂ film (insulating film) in the Si crystal defect portion). In addition, it is possible to suppress the movement (discharge) of electric charges when the diaphragm is brought into contact with or separated from the diaphragm. Accordingly, it is possible to prevent the formation / growth of the polymerized material due to the breakage of the bond between the hydrophobized film 29 made of HMDS and the gap floating material (unreacted HMDS, NH ₃ , intermediate product). Therefore, it is possible to avoid the problem of obstructing the diaphragm operation by the polymer substance, and it is possible to obtain an electrostatic actuator and an inkjet head having stable ejection characteristics and driving durability (reliability).

  In this example, the case where the boron diffusion source is a solid has been described as an example. However, even in the case of a liquid boron diffusion source, the above-described effects can be similarly obtained.

Embodiment 2. FIG.
In the second embodiment, the thermal oxidation process {FIG. 4 (e), (i)} after boron diffusion in the first embodiment is performed by CVD or sputtering to form a SiO ₂ film at a low temperature (400 ° C. or lower). (Not shown).
By adopting the thermal oxidation process at a low temperature in this way, metal impurity precipitation itself can be suppressed, and further quality stabilization can be achieved.

Embodiment 3 FIG.
FIG. 8 is a diagram showing an example of a droplet discharge device including a droplet discharge head to which the electrostatic actuator manufactured in the first and second embodiments is applied. FIG. 8 shows an inkjet recording that particularly discharges ink. An example of the device is shown. An ink jet recording apparatus 100 shown in FIG. 8 is an ink jet printer, and is mounted with either of the droplet discharge heads 10 provided with the electrostatic actuator of the first or second embodiment. Therefore, it is possible to obtain the ink jet recording apparatus 100 that has stable ejection characteristics and driving durability (reliability) and can stably perform high-quality printing.

  The electrostatic actuator according to the first or second embodiment can be applied to an actuator such as a mirror device in addition to the droplet discharge head. In addition to the inkjet printer shown in FIG. 8, the droplet discharge head 10 including the electrostatic actuator of Embodiment 1 or 2 can form a matrix pattern of a color filter by variously changing the liquid to be discharged. The present invention can also be applied to a droplet discharge device that forms a light emitting portion of an organic EL display device, discharges a biological liquid sample, and the like.

2 is an exploded view of a droplet discharge head including the electrostatic actuator according to Embodiment 1. FIG. Sectional drawing of the part which cleaved the part of the discharge chamber in the longitudinal direction. The expanded sectional view of the width direction of the electrostatic actuator part of FIG. FIG. 3 is a manufacturing process diagram of the droplet discharge head of FIG. 1. Explanatory drawing of the boron diffusion method. FIG. 5 is a manufacturing process diagram of the droplet discharge head following FIG. 4. The figure which shows the discharge influence experiment result by the metal impurity containing in a boron diffusion source. FIG. 2 is a schematic configuration diagram of a droplet discharge device including the droplet discharge head according to the first embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle substrate, 2 Cavity substrate, 3 Electrode substrate, 4 Drive control circuit, 10 Inkjet head (droplet discharge head), 11 Ink nozzle, 13 Orifice, 21 Ink chamber, 22 Vibration plate, 23 Reservoir, 26a SiO ₂ film ( Insulating film), 26b SiO ₂ film (ink protective film), 27 Sealing material, 29 Hydrophobized film, 31 Individual electrode, 32 Recessed part, 34 Ink supply hole, 35 Electrode extraction part, 41 Silicon substrate, 41a Cav surface, 41b Dope surface, 42 oxide film, 43 boron doped layer, 44 SiO ₂ film, 45 resist, 51 diffusion source, 52 support substrate, 53 dummy silicon substrate, 54 quartz boat.

Claims (5)

In the method of manufacturing an electrostatic actuator, including a step of forming a boron doped layer on one surface of the Si substrate using a boron diffusion source, and forming the boron doped layer as a diaphragm by an etching stop technique,
A method for manufacturing an electrostatic actuator, wherein a boron diffusion source containing B ₂ O ₃ as a main component and having an Rh content of 0.44 ppm or less is used as a boron diffusion source when forming the boron doped layer. In the method of manufacturing an electrostatic actuator, including a step of forming a boron doped layer on one surface of the Si substrate using a boron diffusion source, and forming the boron doped layer as a diaphragm by an etching stop technique,
The boron diffusion source for forming the boron doped layer is mainly composed of B ₂ O ₃ , Ni content: 2.0 ppm or less, Cu content: 0.5 ppm or less, Rh content: 0.40 ppm or less, Fe A method for producing an electrostatic actuator, comprising using a boron diffusion source having a content of 2.0 ppm or less, a Cr content of 2.0 ppm or less, and a Zn content of 2.0 ppm or less.   3. The method according to claim 1, further comprising the step of forming an oxide film on the Si substrate after boron diffusion, wherein the oxide film is formed by low-temperature film formation by CVD or sputtering. The manufacturing method of the electrostatic actuator in any one of.   A method for manufacturing a droplet discharge head, wherein the method for manufacturing an electrostatic actuator according to claim 1 is applied to manufacture a droplet discharge head. A method for manufacturing a droplet discharge device, wherein the droplet discharge device is manufactured by applying the method for manufacturing a droplet discharge head according to claim 4.

Images