JP2007326195A - Electrode substrate, electrostatic actuator, droplet discharging head, droplet discharging device, electrostatic drive device, and manufacturing method of those - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode substrate having an insulating film which prevents lowering of insulating pressure resistance, does not peel due to repeated collision, and has excellent drive durability; an electrostatic actuator having the electrode substrate, and a manufacturing method thereof. <P>SOLUTION: The manufacturing method comprises a step generating electrostatic force in a space with a vibrating plate 22 which is a moving electrode opposite at a predetermined interval, and forming an individual electrode 12 which is a fixed electrode for displacing the vibrating plate 22 on the electrode substrate 10; and a step alternately repeating deposition processing forming an electrode side insulating film 15 covering at least the individual electrode 12 and surface modification processing washing and surface-modifying of the insulating film, until the electrode side insulating film 15 with required thickness is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic actuator, an electrostatic drive device such as a droplet discharge head, etc., which moves and moves by a force applied by a force applied in a microfabricated element, and a manufacturing method thereof.

  For example, micro electro mechanical systems (MEMS) that process silicon or the like to form microelements and the like have made rapid progress. Examples of microfabricated elements formed by microfabrication technology include, for example, a droplet discharge head (inkjet head), a micropump, and an optical variable filter used in a recording (printing) apparatus such as a droplet discharge type printer. There are electrostatic actuators such as motors.

  Here, a droplet discharge head using an electrostatic actuator will be described as an example of a microfabricated element. A droplet discharge type recording (printing) apparatus is used for printing in various fields regardless of whether it is for home use or industrial use. In the droplet discharge method, for example, a droplet discharge head having a plurality of nozzles is moved relative to an object, and droplets are discharged to a predetermined position of the object to record printing or the like. . This method uses a color filter for manufacturing a display device using liquid crystal, a display panel using an electroluminescence element such as an organic compound (OLED), a microarray of biomolecules such as DNA and protein. Etc. are also used in the manufacture of

  In the droplet discharge head, a discharge chamber for storing liquid in a part of the flow path is provided, and at least one wall of the discharge chamber (here, referred to as a bottom wall, hereinafter referred to as a diaphragm) There is a method in which the pressure in the discharge chamber is increased by changing the shape by bending (being operated), and droplets are discharged from the communicating nozzle. In the case of an electrostatic actuator, for example, a force that displaces the diaphragm that becomes a movable part is generated between a fixed electrode (fixed electrode) that faces the diaphragm with a certain distance from the diaphragm, for example. Electrostatic force (here, particularly electrostatic attraction is used, hereinafter referred to as electrostatic force) is used. As a method for manufacturing such an electrostatic actuator, for example, a glass substrate in which a diaphragm is processed and a fixed electrode (for example, ITO (Indium Tin Oxide)) is formed in a recess on the surface of the substrate. For example, the substrate is generally anodically bonded.

  Further, in the electrostatic actuator using the electrostatic force as described above, in order to prevent short circuit and damage due to contact between the movable electrode (diaphragm) and the fixed electrode and to improve reliability, In some cases, an insulating film is formed on the opposing surface (see, for example, Patent Document 1).

JP 2003-080708 A

  Here, in order to cover the surface of the fixed electrode formed on the glass substrate with an insulating film, it is preferable to form the insulating film at a temperature of 450 ° C. or lower. Therefore, a silicon oxide film forming method using a plasma CVD method (Chemical Vapor Deposition) similar to that for forming an insulating film on silicon can be considered.

  Although not specifically described in the above document, even if a silicon oxide insulating film is formed on a fixed electrode made of ITO in the manner of forming a film on silicon, the silicon oxide film on the fixed electrode has a low withstand voltage, Therefore, sticking due to a short circuit is likely to occur. In addition, since the binding energy is low and the film density is low, there is a problem that the durability against collision is low and the film is easily peeled off due to repeated collision of the diaphragm.

  In view of the above-described problems, the present invention provides an electrode substrate excellent in driving durability characteristics in which an insulating film is not lowered when an insulating film is formed on an electrode and the film is not peeled off even by repeated collisions. An object of the present invention is to provide an electric actuator, a manufacturing method thereof, and the like.

The electrode substrate manufacturing method according to the present invention includes a step of forming a fixed electrode on a substrate for displacing movable electrodes facing each other at a predetermined interval, and a film forming process and an insulation for forming an insulating film covering at least the fixed electrode. And a step of alternately repeating the surface modification treatment for cleaning the film and modifying the surface until an insulating film having a desired thickness is formed.
According to the present invention, the film formation process and the surface modification process are alternately repeated, and the insulating film having a desired thickness is gradually formed while forming a dense film. In addition, it is difficult to drive and film peeling due to sticking, and an excellent electrode substrate can be manufactured.

In the electrode substrate manufacturing method according to the present invention, a silicon oxide film formed by performing a film forming process by a CVD method using TEOS as a raw material is used as an insulating film.
According to the present invention, since TEOS is used as a raw material, a dense film can be formed as compared with other materials.

In the electrode substrate manufacturing method according to the present invention, the surface modification treatment of the insulating film by O ₂ plasma is performed.
According to the present invention, since the surface modification treatment is performed by O ₂ plasma treatment, carbon generated particularly by the decomposition of TEOS can be efficiently removed from the film surface and activated.

In the electrode substrate manufacturing method according to the present invention, the film formation process and the surface modification process for the substrate are performed in the same chamber.
According to the present invention, since a series of processes are performed in the same chamber, it is possible to save troubles such as substrate transportation. In addition, since particles or the like do not adhere, processing can be performed efficiently.

Moreover, the manufacturing method of the electrostatic actuator which concerns on this invention applies said electrode substrate manufacturing method, and manufactures the electrostatic actuator which has a movable electrode.
According to the present invention, since the electrode substrate having the withstand voltage and the driving durability is manufactured and the electrostatic actuator is manufactured, the electrostatic actuator that can be driven stably with a long life can be manufactured.

Also, a manufacturing method of a droplet discharge head according to the present invention applies the above-described manufacturing method of an electrostatic actuator, and manufactures a droplet discharge head that discharges droplets by pressurizing a liquid with a diaphragm serving as a movable electrode. To do.
According to the present invention, since the droplet discharge head having the electrostatic actuator using the electrode substrate having the withstand voltage and the driving durability is manufactured, the droplet that can stably discharge the droplet with a long life. A discharge head can be manufactured.

The manufacturing method of the droplet discharge device according to the present invention applies the above-described manufacturing method of the droplet discharge head to manufacture the droplet discharge device.
According to the present invention, since the droplet discharge device is manufactured by the droplet discharge head having the withstand voltage and the driving durability, it is possible to manufacture a droplet discharge device that has a long life and is stable.

Moreover, the manufacturing method of the electrostatic drive device which concerns on this invention applies a manufacturing method of said electrostatic actuator, and manufactures a device.
According to the present invention, since the device is manufactured by the electrostatic actuator using the electrode substrate having the withstand voltage and the driving durability, it is possible to manufacture the electrostatic driving device that is driven stably with a long life.

The electrode substrate according to the present invention is manufactured by the above manufacturing method.
According to the present invention, it is possible to obtain an electrode substrate that cannot be driven and is unlikely to peel off and has a dielectric strength and driving durability.

An electrostatic actuator according to the present invention includes the above electrode substrate.
According to the present invention, it is possible to obtain an electrostatic actuator that has a withstand voltage and a driving durability, and is driven stably with a long life.

A droplet discharge head according to the present invention includes the electrostatic actuator described above.
According to the present invention, it is possible to obtain a droplet discharge head that has a dielectric strength and driving durability and can discharge droplets stably with a long lifetime.

A droplet discharge apparatus according to the present invention includes the above-described droplet discharge head.
According to the present invention, it is possible to obtain a droplet discharge device that has a withstand voltage and a driving durability and has a long life and is stable.

An electrostatic drive device according to the present invention includes the electrostatic actuator described above.
According to the present invention, it is possible to obtain an electrostatic drive device that has a withstand voltage and a drive durability and can be driven stably with a long life.

Embodiment 1 FIG.
FIG. 1 is an exploded view of a droplet discharge head according to Embodiment 1 of the present invention. FIG. 1 shows a part of the droplet discharge head. In this embodiment, for example, as a representative of a device using an electrostatic actuator driven by an electrostatic method, a face eject type liquid droplet ejection head will be described (in order to illustrate components and make them easy to see, FIG. In addition, in the following drawings, the size relationship of each component may be different from the actual one, and the upper side of the drawing is described as the upper side and the lower side is described as the lower side).

  As shown in FIG. 1, the droplet discharge head according to the present embodiment is configured by laminating three substrates of an electrode substrate 10, a cavity substrate 20, and a nozzle substrate 30 in order from the bottom. In the present embodiment, the electrode substrate 10 and the cavity substrate 20 are bonded by anodic bonding. The cavity substrate 20 and the nozzle substrate 30 are bonded using an adhesive such as an epoxy resin.

The electrode substrate 10 is mainly made of a substrate such as a borosilicate heat-resistant hard glass having a thickness of about 1 mm. In the present embodiment, the glass substrate is used, but single crystal silicon may be used as the substrate, for example. On the surface of the electrode substrate 10, a plurality of recesses 11 having a depth of about 0.3 μm, for example, are formed in alignment with the recesses that become the discharge chambers 21 of the cavity substrate 20 described later. The individual electrodes 12 serving as fixed electrodes are provided inside the recess 11 (particularly at the bottom) so as to face each discharge chamber 21 (vibrating plate 22) of the cavity substrate 20, and the lead portion 13 and the terminal portion 14 are further provided. They are provided integrally (hereinafter, these are collectively described as individual electrodes 12 unless otherwise distinguished). Between the diaphragm 22 and the individual electrode 12, a certain gap (gap) that allows the diaphragm 22 to bend (displace) is formed by the recess 11. The individual electrode 12 is formed by depositing ITO with a thickness of 0.1 μm inside the recess 11 by, for example, sputtering. Further, in the present embodiment, a TEOS film (here, Tetraethyl orthosilicate Tetraethoxysilane: tetraethyl) for electrically insulating the diaphragm 22 and the individual electrode 12 and protecting the individual electrode 12 on the individual electrode 12 is provided. The electrode-side insulating film 15, which is an orthosilicate (which is an SiO ₂ film formed using ethyl silicate) as a source gas), is formed by using a plasma CVD (also referred to as TEOS-pCVD) method to a thickness of about 0.09 μm (90 nm). A film is formed and the individual electrode 12 is covered. By using TEOS as a source gas, a denser film can be formed as compared with the case where a film is formed using another material. In addition, the electrode substrate 10 is provided with a through-hole serving as a liquid supply port 16 serving as a flow path for taking in liquid supplied from an external tank (not shown). A method for manufacturing the electrode substrate 10 including a method for forming the electrode-side insulating film 15 will be described later.

The cavity substrate 20 is mainly made of, for example, a silicon single crystal substrate (hereinafter referred to as a silicon substrate) whose surface is (110) plane orientation. The cavity substrate 20 is formed with a recess that becomes a discharge chamber 21 for temporarily storing a liquid to be discharged (the bottom wall is a vibration plate 22 that becomes a movable electrode) and a recess that becomes a reservoir 24. Further, on the lower surface of the cavity substrate 20 (the surface facing the electrode substrate 10), like the electrode-side insulating film 15, the diaphragm side which is a TEOS film for electrically insulating the individual electrodes 12 and the like. An insulating film 23 is formed to a thickness of 0.1 μm. Here, the diaphragm-side insulating film 23 is formed of a TEOS film, but Al ₂ O ₃ (aluminum oxide (alumina)) or the like may be used, for example. In addition, a recess is formed which becomes a reservoir (common liquid chamber) 24 for supplying a liquid to each discharge chamber 21. Furthermore, a common electrode terminal 27 is provided which serves as a terminal for supplying a charge having a polarity opposite to that of the individual electrode 12 from an external power supply means (not shown) to the substrate (diaphragm 22).

  The nozzle substrate 30 is also mainly made of a silicon substrate, for example. A plurality of nozzle holes 31 are formed in the nozzle substrate 30. Each nozzle hole 31 discharges liquid pressurized by driving the diaphragm 22 to the outside as droplets. If the nozzle holes 31 are formed in a plurality of stages, an improvement in straightness when discharging droplets can be expected. In this embodiment, the nozzle holes 31 are formed in two stages. In the present embodiment, a diaphragm 32 is further provided for buffering the pressure applied in the direction of the reservoir 24 as the diaphragm 22 is bent. Further, an orifice 33 serving as a groove for communicating the discharge chamber 21 and the reservoir 24 is provided.

  FIG. 2 is a cross-sectional view of the droplet discharge head. In FIG. 2, the discharge chamber 21 stores liquid to be discharged from the nozzle hole 31. By deflecting the diaphragm 22 which is the bottom wall of the discharge chamber 21, the pressure in the discharge chamber 21 is increased and liquid droplets are discharged from the nozzle holes 31. Here, in the present embodiment, a high-concentration boron-doped layer that can be used as an electrode and is convenient for the etching process is formed on the silicon substrate to constitute the diaphragm 22. In addition, a sealing material 25 is provided at the electrode outlet 26 in order to block the gap from outside air and seal it so that foreign matter, moisture (water vapor) and the like do not enter the gap.

  For example, the oscillation drive circuit 41 such as a driver IC is electrically connected to the terminal portion 14 and the common electrode terminal 27 via a wiring 42 such as an FPC (Flexible Print Circuit) and a wire, and the individual electrode 12 and the cavity substrate 20 (vibration) The supply and stop of charge (electric power) to the plate 22) are controlled. The oscillation drive circuit 41 oscillates at 24 kHz, for example, and supplies charges by applying pulse potentials of 0 V and 30 V, for example, to the individual electrodes 12. When the oscillation drive circuit 41 oscillates and drives, the electric charge is supplied to the individual electrode 12 to be positively charged, and when the diaphragm 22 is relatively negatively charged, it is attracted to the individual electrode 12 by the electrostatic force and bends. . This increases the volume of the discharge chamber 21. When the supply of electric charge is stopped, the diaphragm 22 returns to its original state, but the volume of the discharge chamber 21 at that time also returns to its original state, and a differential droplet is discharged by the pressure. Recording such as printing is performed when the droplets land on a recording sheet to be recorded, for example.

  FIG. 3 is a diagram illustrating a manufacturing process of the electrode substrate 10. The manufacture of the electrode substrate 10 according to the droplet discharge head will be described with reference to FIG. Actually, a plurality of electrode substrates 10 are simultaneously formed with a wafer-like glass substrate. Then, after bonding with another substrate, etc., the droplet discharge head is manufactured separately, but only a part of the electrode substrate 10 of one droplet discharge head is shown in FIG.

  For example, a chromium (Cr) film 52 is formed to a thickness of 0.03 μm on one surface of a glass substrate 51 of about 1 mm. Further, a gold (Au) film 53 is formed to a thickness of 0.07 μm (FIG. 3A). Here, chromium serves as a base material when the glass substrate is etched using gold as a mask. The chromium film 52 and the gold film 53 are formed by a method such as a CVD method or a physical vapor deposition (PVD) method. For example, as the PVD method, there are methods such as sputtering, vacuum deposition, and ion plating.

  After the gold film 53 is formed, a photoresist (not shown) is applied to the entire surface of the gold film 53. Then, by using a photolithography method, the photoresist photosensitive resin coated on the entire surface of the gold film 53 is exposed with a mask aligner or the like, and developed with a developer. A photoresist pattern for forming a portion to be the recess 11 of the electrode substrate 10 is formed.

  Then, for example, wet etching is performed with hydrochloric acid or sulfuric acid (in the case of the chromium film 52), or a solution containing cyanide ions in the presence of aqua regia or oxygen or water (in the case of the gold film 53), and thereby the gold film 53 and the chromium film are formed. Unnecessary portions of the film 52 are removed. Thereafter, the photoresist is removed. Thereby, the etching pattern of the part used as the recessed part 11 by the chromium film | membrane 52 and the gold film | membrane 53 is formed on the glass substrate 51 (FIG.3 (b)).

  Next, the recess 11 is formed by wet-etching the glass substrate 51 with, for example, a hydrofluoric acid aqueous solution (HF) (FIG. 3C). Then, wet etching is performed to remove the gold film 53 and the chromium film 52 (FIG. 3D). Further, an ITO film 54 to be the individual electrode 12 is formed to a thickness of 0.1 μm on the surface of the glass substrate 51 where the concave portion 11 is formed by sputtering or the like (FIG. 3E). Thereafter, a photoresist (not shown) is further applied to the surface, and a photoresist pattern for forming the individual electrodes 12 is formed using the photolithography method as described above. Then, the ITO film 54 is etched to form the individual electrode 12 (including the lead portion 13 and the terminal portion 14) (FIG. 3 (f)). And the through-hole used as the liquid supply port 16 is formed by the drilling etc., the sandblasting method, etc. (FIG.3 (g)).

FIG. 4 is a diagram showing a processing flow (sequence) in the electrode-side insulating film 15 forming step. In the present embodiment, the electrode-side insulating film 15 that covers the individual electrodes 12 is formed by the procedure as shown in FIG. FIG. 4B shows a conventional procedure performed when a silicon oxide film is formed on silicon. Conventionally, in the sequence of FIG. 4B, the high frequency output is 380 W, the low frequency output is 300 W, the pressure is 333 Pa, and the TEOS flow rate is 130 ml. ^{/ Min (= cm 3 / 60s} ) (130sccm), after 7 seconds film forming process under conditions of an oxygen flow rate of 1200ml / min (1200sccm), carried out for three seconds the surface modification treatment (O ₂ plasma treatment) (S11 to S14).

  As shown in FIG. 4A, first, the glass substrate 51 is placed in the chamber (S1). The following steps are performed in a series of steps in the chamber. The glass substrate 51 in the chamber is heated for about 3 minutes to raise the substrate temperature to about 420 ° C. (S2). First, surface modification treatment was performed for 7 seconds under the conditions of a high-frequency output of 300 W, a pressure of 360 Pa, and an oxygen flow rate of 1000 ml / min (1000 sccm) to clean the glass substrate 51 (including the individual electrodes 12) (especially organic matter) and the surface Modification (activation of the surface by forming a functional group containing oxygen) is performed (S3). In particular, ITO can be expected to improve the electrical characteristics such as work function by surface modification.

  Next, without taking out the glass substrate 51, a film formation process is performed for 2 seconds under conditions of a high frequency output of 300 W, a low frequency output of 400 W, a pressure of 360 Pa, a TEOS flow rate of 80 ml / min (80 sccm), and an oxygen flow rate of 1000 ml / min (1000 sccm). Then, a silicon oxide film 56 to be the electrode-side insulating film 15 is deposited by 0.03 μm (30 nm) to form a film (S4).

  Then, in the same manner as described above, surface modification treatment is performed for 7 seconds under the conditions of a high frequency output of 300 W, a low frequency output of 400 W, a pressure of 360 Pa, and an oxygen flow rate of 1000 ml / min (1000 sccm) to clean the electrode-side insulating film 15. (In particular, removal of carbon and carbon compound (organic matter) formed by decomposition of TEOS) and surface modification (activation) are performed (S5).

  The film formation process and the surface modification process are alternately performed twice (S6 to S9). Finally, an electrode-side insulating film 15 having a thickness of about 0.09 μm (90 nm) is formed (FIG. 3 (h) )). Then, the glass substrate 51 is taken out from the chamber (S10).

  At this stage, since the silicon oxide film is also formed on the terminal portion 14, if it is adhered to the wiring 42 as it is, the electrical characteristics are poor and the charge cannot be supplied. Therefore, a metal mask 61 having an opening at the terminal portion 14 (electrode outlet 26) is attached to the glass substrate 51 taken out, and dry etching is performed to remove the electrode-side insulating film 15 on the terminal portion 14 ( FIG. 3 (i)). After the dry etching is completed, the metal mask 61 is removed to complete the electrode substrate 10 (FIG. 3 (j)).

FIG. 5 is a diagram illustrating a manufacturing process of the droplet discharge head. On the other hand, for example, one side of the silicon substrate 71 (on the side of the bonding surface with the electrode substrate 10) is mirror-polished to obtain a substrate having a thickness of 220 μm (FIG. 5A). Next, the surface on which the boron doped layer 72 of the silicon substrate 71 is formed is set on a quartz boat so as to face a solid diffusion source mainly composed of B ₂ O ₃ , and then set in a vertical furnace, Boron (B) is diffused into the silicon substrate 71 by forming a nitrogen atmosphere, raising the temperature to 1050 ° C. and holding it for 7 hours, thereby forming a boron doped layer 72. Further, on the surface on which the boron doped layer 72 is formed, for example, based on the sequence (S11 to S14) shown in FIG. b)).

  After the silicon substrate 71 and the electrode substrate 10 are heated to, for example, 360 ° C., a negative electrode is connected to the electrode substrate 10 and a positive electrode is connected to the silicon substrate 71, and a voltage of about 800 V is applied to perform anodic bonding. Then, in the substrate after the anodic bonding (hereinafter referred to as a bonded substrate), the surface of the silicon substrate 71 side is ground, wet-etched, etc., so that the thickness of the silicon substrate 71 portion is about 50 μm (FIG. 5C). .

  Next, an etching mask (hereinafter referred to as a TEOS etching mask) 73 made of silicon oxide using TEOS 73 is formed on the surface of the silicon substrate 71 on which wet etching has been performed, as described above. Then, resist patterning of the TEOS etching mask 73 is performed on the portions that become the discharge chamber 21, the reservoir 24, and the electrode outlet 26. These portions of the TEOS etching mask 73 are etched with a hydrofluoric acid aqueous solution, and the TEOS etching mask 73 is patterned. Here, the portion that becomes the discharge chamber 21 is etched until the TEOS etching mask 73 disappears and the silicon substrate is exposed. On the other hand, in the present embodiment, in order to make the bottom portion of the reservoir 24 thick and to ensure rigidity as much as possible, the thickness of the TEOS etching mask 73 is left at 0.3 μm at least for the portion that becomes the reservoir 24. Here, the thickness of the remaining TEOS etching mask 73 is 0.3 μm, but the thickness of the TEOS etching mask 73 is adjusted according to the desired depth of the reservoir 24 (thickness of the bottom portion). Then, after etching, the resist is peeled off (FIG. 5D).

  Next, etching is performed by sequentially immersing the bonded substrate in an aqueous potassium hydroxide solution having a concentration of 35 wt% and 3 wt%. By performing etching using two types of potassium hydroxide aqueous solutions having different concentrations, surface roughness of the diaphragm 22 to be formed can be suppressed and thickness accuracy can be improved. As a result, the discharge performance of the droplet discharge head can be stabilized. When the wet etching is finished, the bonded substrate is immersed in a hydrofluoric acid aqueous solution, and the TEOS etching mask 73 on the surface of the silicon substrate 71 is peeled off (FIG. 5E).

  On the silicon substrate 71, a portion of the silicon that becomes the electrode outlet 26 is removed and opened. Thereafter, sealing is performed by pouring, for example, epoxy resin or depositing silicon oxide along the opening of the gap formed between the cavity substrate 20 at the end of the electrode outlet 26 and each recess 11. A material 25 is formed (FIG. 5F). Further, for example, sputtering is performed using platinum (Pt) as a target to form the common electrode terminal 27. Thereby, the processing performed on the bonded substrate is completed. Although not described in detail here, it is desirable to perform a hydrophobizing process on the gap portion during the above steps.

  The nozzle substrate 30 prepared in advance is bonded from the cavity substrate 20 side of the bonded substrate, for example, with an epoxy adhesive. Then, for example, dicing is performed along a dicing line, and the liquid droplet ejection head is cut into individual liquid droplet ejection heads, thereby completing the liquid droplet ejection head (FIG. 5G). When configuring the apparatus, for example, the wiring 42 connected to the oscillation drive circuit 41 and the terminal portion 14 of the droplet discharge head are joined by an ACF (Anisotropic Conductive Film) or the like.

  FIG. 6 is a diagram showing a durability result of the electrode-side insulating film 15 of the present embodiment. Here, the results of the number of droplet ejection until the occurrence of film peeling is confirmed for the conventional sequence and conditions, the conventional sequence and the conditions of the present embodiment, and the three patterns of the sequence and conditions of the present embodiment are shown. ing. FIG. 6B and FIG. 6C show the film forming process conditions and the surface modification process conditions of the conventional and this embodiment, respectively.

  In the conventional sequence and conditions, the number of ejections was about 50 million to 100 million times, but in the case of the conventional sequence and the conditions of the present embodiment, it becomes about 100 million times. In the case of conditions, it is about 600 million times. From the above, it can be seen that the drive durability is dramatically improved by improving the sequence. Also, with respect to the withstand voltage, what was conventionally 2 MV / cm is 8 MV / cm, which is a significant improvement. Therefore, it is possible to prevent the diaphragm 22 from sticking to the individual electrode 12 due to a short circuit.

As described above, according to the first embodiment, when the electrode-side insulating film 15 is formed, the film forming process and the surface modification process are alternately performed a plurality of times, so that the desired thickness is gradually increased while forming a dense film. Since the electrode-side insulating film 15 is formed, it has much higher withstand voltage and driving durability than the conventional process flow (sequence) for forming a film on a silicon substrate. Inability to drive due to sticking and film peeling hardly occur, and an excellent electrode substrate 10 can be manufactured and obtained. Thereby, it is possible to obtain a droplet discharge head that can stably discharge droplets with a long lifetime. Further, since TEOS is used as the source gas in the film formation process, a dense film can be formed. Furthermore, since the surface modification treatment is performed by O ₂ plasma treatment, carbon (carbon compound) generated by the decomposition of TEOS is effectively removed from the film surface by using carbon dioxide or the like, and oxygen atoms are present on the surface. By linking, activation can be achieved. In addition, since a series of processes related to the film forming process and the surface modification process are performed in the same chamber, it is possible to save time and labor for transporting the substrate. In addition, since particles or the like do not adhere, processing can be performed efficiently.

Embodiment 2. FIG.
In the above-described embodiment, the electrode-side insulating film 15 is formed by alternately performing the film forming process for 2 seconds 3 times and the surface modifying process for 7 seconds 4 times. However, the present invention is not limited to this. For example, when the film formation time is 1 second, a film having a thickness of about 0.01 μm (10 nm) can be formed. By increasing the number of times, a denser film can be formed. Here, if the time of the film forming process is less than 1 second, it becomes difficult to control the pressure, the flow rate, the frequency power, and the like. The film thickness of the electrode-side insulating film 15 formed as described above is not particularly limited, but is desirably at least 0.02 μm (20 nm). However, if it is too thick, it will affect the discharge performance, such as reducing the volume of the gap.

Embodiment 3 FIG.
In the above-described embodiment, an oxide film using TEOS is formed. TEOS is an effective material for forming a dense film. However, in the case of forming a film by, for example, the CVD method, the electrode-side insulating film 15 is formed using another material such as SiH ₄ (monosilane). May be. It is also possible to form a film by sputtering.

  In addition, the film formation in the above-described embodiment is performed on the electrode-side insulating film 15, but for example, a denser film may be formed on the diaphragm-side insulating film 23 by the same method. May be.

Embodiment 4 FIG.
In the above-described embodiment, the liquid droplet ejection head configured by laminating the three substrates of the electrode substrate 10, the cavity substrate 20, and the nozzle substrate 30 has been described. However, the present invention is not limited to this. For example, the present invention can also be applied to a droplet discharge head that includes a discharge chamber and a reservoir formed on separate substrates and configured by stacking four layers of substrates.

Embodiment 5 FIG.
FIG. 7 is an external view of a droplet discharge apparatus (printer 100) using the droplet discharge head manufactured in the above-described embodiment. FIG. 8 is a diagram illustrating an example of main components of the droplet discharge device. 7 and 8 is intended for printing by a droplet discharge method (inkjet method). Further, it is a so-called serial type device. In FIG. 8, a drum 101 that supports a printing paper 110 that is a printing object and a droplet discharge head 102 that discharges ink onto the printing paper 110 and performs recording are mainly configured. Although not shown, there is an ink supply means for supplying ink to the droplet discharge head 102. The print paper 110 is held by being pressed against the drum 101 by a paper press roller 103 provided parallel to the axial direction of the drum 101. A feed screw 104 is provided parallel to the axial direction of the drum 101, and the droplet discharge head 102 is held. As the feed screw 104 rotates, the droplet discharge head 102 moves in the axial direction of the drum 101.

  On the other hand, the drum 101 is rotationally driven by a motor 106 via a belt 105 or the like. Further, the print control unit 107 drives the feed screw 104 and the motor 106 based on the print data and the control signal, and although not shown here, drives the oscillation drive circuit to vibrate the diaphragm 4, Printing is performed on the print paper 110 while controlling.

  Here, the liquid is ejected onto the print paper 110 as ink, but the liquid ejected from the droplet ejection head is not limited to ink. For example, in an application to be discharged onto a substrate to be a color filter, a light emitting element is used in an application to be discharged onto a substrate of a display panel (OLED or the like) using an electroluminescent element such as a liquid containing a color filter pigment or an organic compound For example, a liquid containing a conductive metal and a liquid containing a conductive metal may be discharged from a droplet discharge head provided in each device. In addition, when the droplet discharge head is used as a dispenser and is used for discharging onto a substrate that is a microarray of biomolecules, DNA (Deoxyribo Nucleic Acids: deoxyribonucleic acid), other nucleic acids (for example, Ribo Nucleic Acid: ribonucleic acid, Peptide (Nucleic Acids: peptide nucleic acids, etc.) A liquid containing a probe such as a protein may be discharged. In addition, it can also be used for discharging dyes such as cloth.

Embodiment 6 FIG.
FIG. 9 is a diagram showing a wavelength tunable optical filter using the present invention. In the above-described embodiment, the droplet discharge head has been described as an example. However, the present invention is not limited to the droplet discharge head, and may be applied to an electrostatic type device using an electrostatic actuator by other fine processing. can do. For example, the wavelength tunable optical filter shown in FIG. 9 uses the principle of a Fabry-Perot interferometer and outputs light of a selected wavelength while changing the distance between the movable mirror 120 and the fixed mirror 121. In order to displace the movable mirror 120, the movable body 122 made of silicon and provided with the movable mirror 120 is displaced. For this purpose, the fixed electrode 123 and the movable body 122 (movable mirror 120) are arranged to face each other at a predetermined interval (gap). Here, a film may be formed by the above-described method on the electrode-side insulating film 126 provided on the fixed electrode 123.

  Similarly, the above-described sealing portion is also formed on other types of microfabricated actuators such as motors, sensors, SAW filters, resonator elements such as SAW filters, tunable optical filters, mirror devices, and pressure sensors. Etc. can be applied.

2 is an exploded view of a droplet discharge head according to Embodiment 1. FIG. It is sectional drawing of a droplet discharge head. 3 is a diagram illustrating a manufacturing process of the electrode substrate 10. FIG. FIG. 6 is a diagram illustrating a manufacturing process (No. 1) of the droplet discharge head according to the first embodiment. FIG. 6 is a diagram illustrating a manufacturing process (No. 2) of the droplet discharge head according to the first embodiment. It is a figure showing the endurance result of electrode side insulating film 15 of this embodiment. It is an external view of a droplet discharge device using a droplet discharge head. It is a figure showing an example of the main structural means of a droplet discharge apparatus. It is a figure showing the wavelength variable optical filter using this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrode substrate, 11 Recessed part, 12 Individual electrode, 13 Lead part, 14 Terminal part, 15 Electrode side insulating film, 16 Liquid supply port, 20 Cavity board, 21 Discharge chamber, 22 Vibration plate, 23 Vibration plate side insulating film, 24 Reservoir, 25 Sealing material, 26 Electrode outlet, 27 Common electrode terminal, 30 Nozzle substrate, 31 Nozzle hole, 32 Diaphragm, 33 Orifice, 41 Oscillation drive circuit, 42 Wiring, 51 Glass substrate, 52 Chrome film, 53 Gold film , 54 ITO film, 61 metal mask, 71 silicon substrate, 72 boron doped layer, 73 etching mask, 100 printer, 101 drum, 102 droplet discharge head, 103 paper pressure roller, 104 feed screw, 105 belt, 106 motor, 107 print Control means, 110 print paper, 120 movable mirror, 121 fixed mirror, 12 2 movable body, 123 fixed electrode, 124 fixed electrode terminal, 125 sealing material, 126 electrode side insulating film.

Claims (13)

Forming a fixed electrode on the substrate for displacing the movable electrodes facing each other at a predetermined interval;
A step of alternately repeating a film forming process for forming an insulating film covering at least the fixed electrode and a surface modifying process for cleaning and surface modifying the insulating film until an insulating film having a desired thickness is formed; A method for manufacturing an electrode substrate, comprising:   2. The method of manufacturing an electrode substrate according to claim 1, wherein the insulating film is a silicon oxide film formed by performing a film forming process by a CVD method using TEOS as a raw material. The method for manufacturing an electrode substrate according to claim 1, wherein the surface modification treatment of the insulating film is performed by O ₂ plasma.   The method for manufacturing an electrode substrate according to claim 1, wherein the film forming process and the surface modification process for the substrate are performed in the same chamber.   A method for manufacturing an electrostatic actuator, comprising applying the method for manufacturing an electrode substrate according to claim 1 to manufacture an electrostatic actuator having the movable electrode.   6. A droplet discharge head that applies the method for manufacturing an electrostatic actuator according to claim 5 to manufacture a droplet discharge head that discharges droplets by pressurizing a liquid with a vibration plate serving as the movable electrode. Manufacturing method.   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 6.   A method for manufacturing an electrostatic drive device, wherein the device is manufactured by applying the method for manufacturing an electrostatic actuator according to claim 5.   An electrode substrate manufactured by the manufacturing method according to claim 1.   An electrostatic actuator comprising the electrode substrate according to claim 9.   A droplet discharge head comprising the electrostatic actuator according to claim 10.   A droplet discharge apparatus comprising the droplet discharge head according to claim 11. An electrostatic drive device comprising the electrostatic actuator according to claim 10.

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