JP2007111910A - Electrostatic actuator, liquid droplet delivering head, liquid droplet delivering apparatus and electrostatic device and their manufacturing method, and mask substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electrostatic actuator capable of attaching a sealing material only to a required part and thereby efficiently performing a sure sealing, a liquid droplet delivering head, a liquid droplet delivering apparatus, an electrostatic device and their manufacturing methods, and to obtain an appropriate mask used for attaching the sealing material at a specified part. <P>SOLUTION: A process wherein a through-channel hole 26 for forming a sealing material 25 intercepting a space formed between an individual electrode 12 and a vibrating plate 22 from the open air within a required range is formed on one of an electrode substrate 10 with the individual electrode 12 or a cavity substrate 20 opposing the individual electrode 12 by a distance and having the vibrating plate 22 being a movable electrode operated by a static electric force generated between it and the individual electrode 12, and a process wherein the mask 200 in which the part of the through-channel hole 26 is opened is fitted on a connecting substrate connecting the electrode substrate 10 and the cavity substrate 20, and a process wherein a sealing part is formed on the connecting substrate by sealing the sealing material 25 from the through-channel hole 26, are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an electrostatic actuator, an electrostatic device such as a droplet discharge head, etc., in which a movable part is displaced by an applied force and the like in a microfabricated element, an apparatus using the device, and a manufacturing method thereof. Is. In particular, it relates to sealing performed with microfabricated elements.

  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, pressure sensors and the like.

  Here, a droplet discharge head that is 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. The droplet discharge method is, for example, a method in which a droplet discharge head having a plurality of nozzles is moved relative to an object (paper, etc.), and a droplet is discharged to a predetermined position of the object for printing or the like. It is. 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 is provided in a part of the flow path, 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 deforming (being operated) and discharging the droplets from the communicating nozzle. As a force for displacing the diaphragm that becomes the movable electrode, for example, an electrostatic force (often using an electrostatic attractive force) generated between the electrode (fixed electrode) facing the diaphragm at a distance is used. ing.

  Here, in the electrostatic actuator using the electrostatic force as described above, when water or the like adheres between at least one surface between the movable electrode (the vibration plate in the droplet discharge head) and the fixed electrode, water or the like There is a possibility that the electrostatic attraction characteristics may be deteriorated due to charging of polar molecules. Furthermore, polar molecules may hydrogen bond with each other, and the movable electrode may stick to the fixed electrode, making it inoperable. Therefore, it is desirable to block the surroundings of the movable electrode and the fixed electrode from the outside air. Here, it is possible to almost block the periphery of the movable electrode and the fixed electrode by bonding the base substrates, but if it is completely blocked, it is difficult to supply power (charge) from the outside to the individual electrodes. Therefore, an opening for taking out the electrode is provided in a part. The opening that cannot be blocked by the substrate is sealed with a sealing material (sealing member), etc., while ensuring electrical connection, and hermetically sealed to prevent intrusion of moisture and the like. (For example, refer to Patent Document 1).

JP 2002-1972

  As described above, when the opening is sealed with a sealing material to perform hermetic sealing, for example, in the process of formation, the sealing material originally does not need sealing, for example, bonded to another substrate. If it adheres to the part that becomes the terminal of the taken-out electrode or the extracted electrode, it interferes with the bonding with another substrate and the electrical connection with the power supply means, causing a bonding failure and a connection failure. Therefore, in order to prevent these defects, a step of removing the sealing material must be further performed. In the removing step, the sealing material is scraped off, washed, and the like, but this increases the possibility of generation of foreign matters such as dust generation, and the efficiency becomes poor in terms of time.

  Therefore, in order to solve such problems, the present invention provides an electrostatic actuator, a droplet discharge head, and a droplet discharge device that can efficiently perform reliable sealing by attaching a sealing material only to a desired portion. And an electrostatic device and a method of manufacturing the same. Furthermore, it aims at obtaining the suitable mask board | substrate used in order to adhere a sealing material to a predetermined part.

The method for manufacturing an electrostatic actuator according to the present invention includes a first substrate having a fixed electrode, or a first electrode having a movable electrode that is opposed to the fixed electrode at a distance and operates by electrostatic force generated between the fixed electrode and the fixed electrode. Forming a through-slot hole in one of the two substrates for forming a sealing material for blocking a space formed between the fixed electrode and the movable electrode from outside air within a desired range; and a through-slot hole part A step of attaching a mask substrate having an opening to a bonded substrate obtained by bonding the first substrate and the second substrate, and a step of encapsulating a sealing material from the through-groove hole to form a sealing portion on the bonded substrate. .
According to the present invention, the through-slot hole is provided as a sealing portion, the through-slot hole is used as a wall, and the other part is masked with the mask substrate, so that the first substrate and the second substrate are within a desired range. Since the sealing material is formed, for example, when forming the sealing material by depositing the sealing material by sputtering or the like, the fixed electrode to which the sealing material should not be originally attached and the external power supply means Can be prevented from adhering to the contact point, and connection failure can be prevented, reliable sealing can be performed, and the service life can be extended.

In addition, the manufacturing method of the electrostatic actuator according to the present invention is such that the bonding substrate and the mask substrate are connected to each other with respect to the surface of the bonding substrate made of silicon and the mask substrate before the step of attaching the mask substrate to the bonding substrate. The method further includes a step of cleaning the contacting surface by an O ₂ plasma method.
According to the present invention, the surfaces of the bonding substrate and the mask substrate that are in contact with each other are cleaned by the O ₂ plasma method, and then the mask substrate is attached to the bonding substrate. In this case, the sealing material can be prevented from wrapping around.

In addition, the electrostatic actuator manufacturing method according to the present invention contacts the mask substrate of the bonded substrate with respect to the surface of the bonded substrate made of silicon and the mask substrate before the step of attaching the mask substrate to the bonded substrate. The method further includes a step of cleaning the surface by an O ₂ plasma method, and cleaning the surface of the mask substrate in contact with the bonding substrate with ammonia overwater.
According to the present invention, with respect to the surfaces of the bonding substrate and the mask substrate that are in contact with each other, the mask substrate side is cleaned with ammonia overwater, and the bonding substrate side is cleaned with an O ₂ plasma method so that liquid does not enter the space or the like. As a result, the surfaces in contact with each other can be brought into close contact with each other by hydrogen bonding, thereby preventing the sealing material from wrapping around during the sealing process.

Moreover, the manufacturing method of the electrostatic actuator which concerns on this invention wash | cleans the surface which contact | connects the joining board | substrate of a mask board | substrate with sulfuric acid hydrogen peroxide instead of ammonia hydrogen peroxide.
According to the present invention, even with sulfuric acid / hydrogen peroxide, the surfaces in contact with each other can be brought into close contact with each other by hydrogen bonding, as with ammonia / hydrogen peroxide, so that the sealing material can be prevented from wrapping around during the sealing process.

Further, in the method for manufacturing an electrostatic actuator according to the present invention, at least one of the surface of the bonding substrate that contacts the mask substrate and the surface of the mask substrate that contacts the bonding substrate is provided with minute irregularities.
According to the present invention, since the contact area is reduced by providing minute unevenness, the hydrogen bond is not too strong, and the bonding substrate and the mask substrate can be easily separated after the sealing step.

Moreover, the manufacturing method of the electrostatic actuator which concerns on this invention encloses a sealing material by CVD method.
According to the present invention, a sealing material can be easily deposited and sealed by a commonly used CVD method.

Moreover, the manufacturing method of the electrostatic actuator according to the present invention encapsulates the sealing material by sputtering.
According to the present invention, a sealing material can be easily deposited and sealed by a commonly used sputtering method.

The manufacturing method of the droplet discharge head according to the present invention applies the above-described electrostatic actuator manufacturing method to manufacture the droplet discharge head.
According to the present invention, since a sealing portion can be formed within a desired range and reliable sealing can be performed, a long-life droplet 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 head in which the sealing material is sealed in the through groove hole and the reliable sealing portion is formed is used, a long-life droplet discharge device can be manufactured.

Moreover, the manufacturing method of the electrostatic device according to the present invention applies the above-described manufacturing method of the electrostatic actuator to manufacture the electrostatic device.
According to the present invention, since the electrostatic actuator in which the sealing material is sealed in the through groove hole and the reliable sealing portion is formed is used, it is possible to manufacture a long-life electrostatic device.

In addition, the mask substrate according to the present invention is a second substrate having a movable electrode that is opposed to the first electrode having a fixed electrode and the fixed electrode at a distance and operates by electrostatic force generated between the fixed electrode and the first substrate. The opening part corresponding to the through-slot hole for forming the sealing material which interrupts | blocks the space formed between a fixed electrode and a movable electrode with external air in a desired range is provided.
According to the present invention, since the opening portion corresponding to the through groove hole is provided, a mask capable of selectively forming a sealing material can be obtained.

The mask substrate according to the present invention is made of silicon.
According to the present invention, since the mask substrate is made of silicon, the position and size of the opening can be easily formed with high accuracy by an etching process.

In addition, the mask substrate according to the present invention has a communication groove on the surface in contact with the electrostatic actuator for communicating the recess formed in the electrostatic actuator with the outside.
According to the present invention, since the communication groove is provided on the surface in contact with the electrostatic actuator, it is possible to prevent the concave portion formed in the electrostatic actuator from being sucked and sucked. The substrate and the mask substrate can be easily separated.

A method for manufacturing a mask substrate according to the present invention comprises forming the opening of the mask substrate as described above by etching the substrate.
According to the present invention, by forming the opening portion of the mask substrate by etching, a mask substrate having an opening portion in a size at a desired position can be manufactured.

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, a face eject type liquid droplet ejection head will be described as a representative device using an electrostatic actuator driven by an electrostatic method. (In addition, in order to make the components shown and easy to see, the relationship between the sizes of the components in the following drawings including FIG. 1 may be different from the actual one. Explain with the side down).

  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. Here, 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 serving as the first substrate is mainly made of a substrate such as 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, for example, about 0.3 μm are formed in accordance with a recess that becomes a discharge chamber 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 (Indium Tin Oxide) with a thickness of 0.1 μm inside the recess 11 by sputtering, for example. In addition, the electrode substrate 10 is provided with a through-hole serving as a liquid intake port 15 serving as a flow path for taking in liquid supplied from an external tank (not shown).

The cavity substrate 20 serving as the second substrate is mainly made of, for example, a silicon single crystal substrate (hereinafter referred to as a silicon substrate) having a (100) plane orientation (or (110) plane orientation). The cavity substrate 20 has a recess (a bottom wall is a vibrating plate 22 serving as a movable electrode) serving as a discharge chamber 21 for temporarily storing a liquid to be discharged, and a sealing material 25 of the lead portion 13 as described later. A through-groove hole 26 is formed in the portion directly above to form the sealing portion 26a. Further, a TEOS film (here, Tetraethyl orthosilicate Tetraethoxysilane: tetraethoxysilane) for electrically insulating the diaphragm 22 and the individual electrodes 12 is formed on the lower surface of the cavity substrate 20 (surface facing the electrode substrate 10). The insulating film 23 (which is an SiO ₂ film made of ethyl silicate) is formed to a thickness of 0.1 μm by using a plasma CVD (Chemical Vapor Deposition: TEOS-pCVD) method. Although the insulating film 23 is a TEOS film here, for example, Al ₂ O ₃ (aluminum oxide (alumina)) may be used. In addition, a recess is formed which becomes a reservoir (common liquid chamber) 31 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 7 from an external power supply means (not shown) to the substrate (diaphragm 22). An orifice 29 serving as a groove for communicating the discharge chamber 5 and the reservoir 7 is provided.

  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 pressure applied in the direction of the reservoir 28 as the diaphragm 22 bends.

  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.

The oscillation drive circuit 41 is electrically connected to the terminal portion 14 and the common electrode terminal 27 via a wire 42 such as a wire or an FPC (Flexible Print Circuit), and charges the individual electrode 12 and the cavity substrate 20 (the vibration plate 22). (Electric power) supply and stop are controlled. The oscillation drive circuit 41 oscillates at, for example, 24 kHz, and supplies electric charges by applying pulse potentials of 0 V and 30 V to the individual electrodes 12. When the oscillation drive circuit 41 is driven to oscillate, when an electric charge is supplied to the individual electrode 12 to be positively charged and the diaphragm 22 is relatively negatively charged, it is attracted to the individual electrode 12 by an 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.
Further, the sealing material 25 is provided to block and seal the gap from outside air so that foreign matter, moisture (water vapor) and the like do not enter the gap.

  FIG. 3 is a view showing the concept of the relationship between the through-slot 26 provided in the cavity substrate 20 and the lead portion 13 on the electrode substrate 10. As shown in FIG. 3, in the present embodiment, a through-slot hole 26 for exposing the lead portion 13 is provided in the cavity substrate 20. Here, the narrower the width in the longitudinal direction of the through-slot hole 26, the more the size can be reduced. However, if the width is too narrow, it may not be deposited well, so it is desirable that the thickness is 10 μm to 20 μm. In some cases, the thickness of the cavity substrate 20 may be limited during processing (particularly in the case of a silicon substrate having a (100) plane orientation), and is not particularly limited to 10 μm to 20 μm. If reliable sealing is possible, the width may be 300 μm (0.3 mm), for example. Further, as the sealing material 25 to be deposited, here, silicon oxide (inorganic compound) having high insulation and hermetic sealing ability and having resistance to acidic and alkaline solutions used for cleaning or the like is used. The thickness of the deposited sealing material 25 is, for example, at least a gap width (about 0.18 μm) or more. It is desirable that the thickness is about 2 to 3 μm or more as long as the bonding with the reservoir substrate 30 is not affected.

A space from the opening portion of the through groove hole 26 to the cavity substrate 20 from the lead portion 13 portion of the electrode substrate 10 by a method such as CVD (Chemical Vapor Deposition), (ECR) sputtering, or vapor deposition. Silicon oxide (SiO ₂ ), which is the sealing material 25, is deposited on (a part of the gap) to form the sealing portion 26a, and the gap is shut off from the outside air to prevent entry of moisture, foreign matter, and the like. Here, silicon oxide (SiO ₂ ) is used. For example, Al ₂ O ₃ (aluminum oxide (alumina)), silicon nitride (SiN), silicon oxynitride (SiON), Ta ₂ O ₅ (five Tantalum oxide), DLC (Diamond Like Carbon), polyparaxylylene, PDMS (polydimethylsiloxane: a kind of silicone rubber), inorganic or organic compounds such as epoxy resin, etc., for example, relatively low molecular weight, vapor deposition, sputtering, etc. It is possible to use a substance that can be deposited by water and impermeable to moisture.

Conventionally, the sealing material 25 is formed by applying and curing an epoxy resin to a portion (a portion of the terminal portion 14) opened between the electrode substrate 10 and the cavity substrate 20 by the recess 11. However, when using an epoxy resin, it is necessary to make the lead part 13 sufficiently long so that it does not enter between the individual electrode 12 and the diaphragm 22 due to a capillary phenomenon or the like, which has been an obstacle to downsizing. Therefore, there is a method in which a sealing material such as SiO ₂ is deposited on the opening by vapor deposition, sputtering, etc. However, since the space serving as the electrode outlet 24 is wide, even if a mask or the like is attached, the material wraps around. It is difficult to deposit the sealing material 25 only on a predetermined portion of the electrode outlet 24. Therefore, the sealing material 25 may be deposited and adhered to a portion that should not be deposited. For example, if the sealing material 25 is deposited on the connection portion between the terminal portion 14 and the wiring 52, the terminal portion 14 and the wiring 52 cannot be electrically connected well, and the connection is poor (conductivity failure). May occur.

  In order to prevent poor connection, an extra step of removing the sealing material is necessary. However, this step not only consumes time but also causes foreign matters and affects other members. Therefore, in the present embodiment, the sealing material 25 is selectively deposited and sealed only at a desired location, and the through groove is formed in accordance with the location so that the sealing portion 26a can be efficiently formed. The hole 26 is opened. Thereby, a mask (described later) having an opening corresponding to the through-slot hole 26 is attached, and the through-slot hole 26 becomes a wall surrounding the periphery, and the sealing material 25 is deposited only at a desired location (directly above the lead portion 13). Then, the sealing portion 26a is formed.

  4 and 5 are diagrams showing a manufacturing process of the droplet discharge head according to the first embodiment. The droplet discharge head manufacturing process will be described with reference to FIGS. Actually, a plurality of droplet discharge head members are simultaneously formed for each wafer, but only a part thereof is shown in FIGS.

One side of the silicon substrate 51 (becomes the bonding surface side with the electrode substrate 10) is mirror-polished to produce, for example, a 220 μm thick substrate (becomes the cavity substrate 20). Next, the surface of the silicon substrate 51 on which the boron doped layer 52 is to be formed is opposed to a solid diffusion source mainly composed of B ₂ O ₃ , and boron is diffused into the silicon substrate 51 by being placed in a vertical furnace. Layer 52 is formed. Then, on the surface on which the boron doped layer 52 is formed, the plasma CVD method is used, the processing temperature during film formation is 360 ° C., the high frequency output is 250 W, the pressure is 66.7 Pa (0.5 Torr), and the gas flow rate is TEOS flow rate 100 cm ³ / The insulating film 23 is formed to a thickness of 0.1 μm under the conditions of min (100 sccm) and oxygen flow rate of 1000 cm ³ / min (1000 sccm) (FIG. 4A).

  The electrode substrate 10 is manufactured in a separate process from the above (a). Etching or the like is performed on one surface of a glass substrate of about 1 mm to form a recess 11 having a depth of about 0.3 μm. After the formation of the recess 11, the individual electrode 12 having a thickness of 0.1 μm is simultaneously formed by using, for example, a sputtering method. Finally, a hole to be the liquid intake 15 is formed by a sandblasting method or a cutting process. In some cases, this produces the electrode substrate 10. And after heating the silicon substrate 51 and the electrode substrate 10 to 360 degreeC, a negative electrode is connected to the electrode substrate 10, a positive electrode is connected to the silicon substrate 51, the voltage of 800V is applied, and anodic bonding is performed (FIG.4 (b)). ).

  Grinding of the surface of the silicon substrate 51 is performed until the thickness of the silicon substrate 51 becomes about 60 μm with respect to the substrate (hereinafter referred to as a bonded substrate) after the anodic bonding. Thereafter, in order to remove the work-affected layer, the silicon substrate 51 is subjected to about 10 μm anisotropic wet etching (hereinafter referred to as wet etching) with a potassium hydroxide solution. As a result, the thickness of the silicon substrate 51 is reduced to about 50 μm (FIG. 4C).

A silicon oxide hard mask (hereinafter referred to as a TEOS hard mask) 53 by TEOS is formed on the surface of the bonding substrate subjected to wet etching by plasma CVD. As film formation conditions, for example, the processing temperature during film formation is 360 ° C., the high frequency output is 700 W, the pressure is 33.3 Pa (0.25 Torr), the gas flow rate is TEOS flow rate 100 cm ³ / min (100 sccm), and the oxygen flow rate is 1000 cm ^3. / Min (1000 sccm), and a film thickness of 1.5 μm is formed under the conditions. Film formation by plasma CVD using TEOS can be performed at a relatively low temperature, and heating of the substrate can be suppressed (FIG. 4D).

  After the TEOS hard mask 53 is formed, resist patterning is performed in order to etch the TEOS hard mask 53 in the portions that become the discharge chamber 21, the reservoir 28, the through groove 26, and the electrode outlet 24. Then, these portions are etched using the hydrofluoric acid aqueous solution until the TEOS hard mask 53 disappears, and the TEOS hard mask 53 is patterned, and the silicon substrate 51 is exposed for these portions. Then, after the etching, the resist is peeled off (FIG. 4E). Here, for example, with respect to the portion that becomes the electrode outlet 24 that has a large area and is easily cracked, the resist thickness is left slightly, so that a thickness for preventing cracking is left in a later step. Also good.

  Next, the bonded substrate is dipped in a 35 wt% potassium hydroxide aqueous solution, and anisotropic wet etching (hereinafter, referred to as “removal chamber”) is performed until the thicknesses of the discharge chamber 21, the through groove 26, and the electrode outlet 24 become about 10 μm. (Wet etching). Further, the bonded substrate is immersed in a 3 wt% potassium hydroxide aqueous solution, the boron doped layer 52 is exposed, and the wet etching is continued until it is judged that the etching stop that the etching progresses extremely slowly is effective (FIG. 5). (F)). In this way, by performing etching using two types of potassium hydroxide aqueous solutions having different concentrations, it is possible to suppress surface roughness of the diaphragm 22 formed in the portion serving as the discharge chamber 21 and to increase the thickness accuracy. As a result, the discharge performance of the droplet discharge head can be stabilized.

When the wet etching is completed, the bonding substrate is immersed in a hydrofluoric acid aqueous solution, and the TEOS hard mask 53 on the surface of the silicon substrate 51 is peeled off. Next, in order to remove the boron doped layer 52 in the portion that becomes the through groove hole 26 and the electrode extraction port 24, a silicon mask in which the portion that becomes the through groove hole 26 and the electrode extraction port 24 is opened is connected to the silicon substrate 51 side of the bonding substrate. Attach to the surface. Then, for example, RIE dry etching (anisotropic dry etching) is performed for 30 minutes under the conditions of an RF power of 200 W, a pressure of 40 Pa (0.3 Torr), and a CF ₄ flow rate of 30 cm ³ / min (30 sccm). Plasma is applied only to the portion that becomes the electrode outlet 24 to open (FIG. 5G). Here, for example, in order to increase the alignment accuracy between the bonding substrate and the mask, the silicon mask may be mounted by pin alignment in which pins are passed between the bonding substrate and the silicon mask. Here, the openings are formed by anisotropic dry etching, but the boron doped layer 52 may be broken by protruding with pins or the like.

  FIG. 6 is a diagram showing an outline of the shapes of a sealing mask substrate 60 (hereinafter referred to as a mask 60) and a bonding substrate. 6A and 6B show a surface and a side surface where the mask 60 is in contact with the bonding substrate, respectively. FIG. 6C shows the upper surface of the corresponding bonded substrate (cavity substrate 20). Here, the schematic shapes for two rows are described, but more rows are formed on the actual substrate (wafer), and the number of droplet discharge heads (chips) in each row is further increased. Many.

  The material of the mask 60 is not particularly limited, and the mask 60 may be made of a metal such as chromium. However, in this embodiment mode, silicon that can easily produce a high-precision mask using an etching process is used as a material. To do. For the silicon substrate, patterning is performed in accordance with the portion of the through-groove 26 of the bonding substrate, and patterning is performed in correspondence with the concave portion formed in the bonding substrate on the surface in contact with the bonding substrate, A hard mask of silicon oxide is formed. Then, for example, wet etching is performed with a hydrofluoric acid aqueous solution or the like to form the opening 210 and the air opening groove 211. Here, the opening 210 and the air opening groove 211 are formed by wet etching, but may be formed by dry etching, for example.

  As described above, in the mask 60, the mask opening 210 is provided in a portion corresponding to the through groove hole 26. Here, the opening portion of the mask opening 61 on the surface side in contact with the bonding substrate is the opening portion of the through-slot hole 26 so that the sealing material 25 does not adhere to the surface of the cavity substrate 20 (the bonding surface with the nozzle substrate 30). It is desirable to keep it smaller. In addition, an air release groove 211 is provided on the side in contact with the bonding substrate. The atmosphere opening groove 62 allows the space and the outside to communicate with each other so that the space formed by the recess and the mask 60 is not completely sealed by mounting the mask 60. This is because when the pressure in the space formed by the mask 60 and the bonding substrate being in close contact with each other is low, the mask 60 becomes like a suction cup and is prevented from adsorbing to the bonding substrate. In this embodiment, the discharge chamber 21, the concave portion that becomes the reservoir 28, and the opening portion that becomes the electrode outlet 24 are communicated with the outside. Here, the air release groove 62 is formed along the short direction of the discharge chamber 21 so that the recesses forming the discharge chambers 21 in a row communicate with the outside. Although it is conceivable to provide the air release grooves 62 along the longitudinal direction of the recesses to be the discharge chambers 21, in this case, the air release grooves 62 must be provided in proportion to the number of discharge chambers 21 (nozzles) forming a row. Rather, the number of grooves increases. In addition, it is desirable that the portion communicating with the outside is provided in a portion where the material to be the sealing material 25 does not go into the recess or the like.

The produced mask 60 and the surface of the bonding substrate on the side of the silicon substrate 51 are subjected to O ₂ plasma cleaning to clean the respective surfaces. In this state, the mask 60 is attached to the surface of the bonding substrate on the silicon substrate 51 side. The mask 60 that has been subjected to O ₂ plasma cleaning and the bonding substrate are subjected to hydrogen bonding by a hydroxyl group (OH), thereby preventing the material serving as the sealing material 25 from wrapping around without causing a gap at least on the outer peripheral surface. . In this case as well, the alignment between the mask 60 and the bonding substrate may be performed by pin alignment. Then, for example, the sealing material 25 is deposited on the through groove 26 by CVD (including plasma CVD using TEOS), sputtering, vapor deposition, or the like, thereby forming the sealing portion 26a (FIG. 5H). The thickness of the sealing material 25 to be deposited is not particularly limited as described above, but since the gap width is about 0.2 μm, the thinnest portion has a thickness of about 2 to 3 μm or more, and other substrates. It suffices if it can be deposited in a range that does not affect the bonding of the film.

  When the sealing is completed, for example, a mask having an opening at a portion that becomes the common electrode terminal 27 is attached to the surface of the bonding substrate on the silicon substrate 51 side. Then, for example, sputtering is performed using platinum (Pt) as a target to form the common electrode terminal 27. And the nozzle board | substrate 30 produced by the separate process previously is adhere | attached and bonded from the cavity board | substrate 20 side of a joining board | substrate, for example with an epoxy-type adhesive agent (FIG.5 (i)). Then, dicing is performed along the dicing line, and cutting into individual droplet discharge heads is completed.

As described above, according to the first embodiment, the through hole 26 is provided in the cavity substrate 20 and, for example, SiO ₂ (silicon oxide) is sealed only in the portion directly above the lead portion 13 via the through groove 26. Since the sealing part 26a as the material 25 is formed and the gap (gap) of the part formed at the opposed part of the diaphragm 22 and the individual electrode 12 is blocked from the outside air, the through-slot hole 26 becomes a wall, By forming the sealing portion 26a by deposition or the like within the selected range (the range of the through groove hole), the sealing portion 26a can be more efficiently and reliably formed. Further, in the step of forming the sealing portion 26 a, the excess sealing material 25 does not adhere to the terminal portion 14 due to the mask 60 in the portion of the electrode outlet 24. Therefore, connection failure can be prevented without impairing the electrical connection with the wiring or the like without performing the removal step. Since the sealing material 25 is deposited by sputtering, CVD, vapor deposition, etc., sealing can be performed reliably, and a plurality of wafers can be sealed at once, and at the time of manufacturing Very efficient.

In addition, since the mask 60 used in the sealing step is made of silicon, a highly accurate mask can be manufactured in an opening position, an opening area, and the like by using an etching process. And since the air release groove | channel 62 was provided in the surface which contact | connects the joining board | substrate of the mask 60, it can prevent that the mask 60 adheres to the recessed part of a joining board | substrate, and is further adsorb | sucked. Further, since the mask 60 and the bonding substrate are subjected to, for example, O ₂ plasma cleaning, hydrogen bonding is performed by hydroxyl groups on the respective surfaces obtained by the cleaning, so that the bonding substrate surface and the mask 60 are in close contact with each other. Therefore, wraparound of the material that becomes the sealing material 25 can be prevented.

Embodiment 2. FIG.
In the above-described embodiment, the mask 60 and the bonding substrate are both subjected to O ₂ plasma cleaning before the mask 60 is attached to the surface of the bonding substrate on the silicon substrate 51 side. However, the present invention is not limited to this. For example, cleaning (APM cleaning, SC1 cleaning) by ammonia perwater (a solution of ammonia hydrogen peroxide water mixed with ammonia and hydrogen peroxide water, diluting with water in some cases), sulfuric acid hydrogen peroxide (sulfuric acid and hydrogen peroxide) Similarly, hydrogen bonding on the surface can be performed by performing cleaning (SPM cleaning, piranha cleaning) or the like with a solution of sulfuric acid and hydrogen peroxide mixed with water.

  However, if the bonding substrate before sealing is washed with liquid ammonia or hydrogen peroxide, it may be contaminated with liquid residue. Therefore, it is desirable that only the mask 60 be washed with ammonia-hydrogen peroxide or sulfuric acid-hydrogen peroxide.

Embodiment 3 FIG.
In the above-described embodiment, the mask 60 and the bonding substrate are hydrogen-bonded to prevent wraparound. However, if the mask 60 and the bonding substrate are both smooth and hydrogen bonding as described above is performed on the entire surface, the force due to bonding becomes too strong and the mask 60 cannot be easily removed from the bonding substrate.

  Therefore, at least one of the mask 60 and the bonding surface of the bonding substrate is not mirror-finished (mirror-polished) so that it can be easily removed while being appropriately bonded to prevent wraparound. The unevenness may be left and the contact (adhesion) area may be reduced to weaken the force. Further, only the periphery of the wafer and the periphery of the mask opening 61 may be in close contact so that the material to be the sealing material 25 does not enter.

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 of FIG. 10 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, the fixed electrode terminal 124 is taken out to supply charges to the fixed electrode. At that time, in order to ensure airtight sealing between the substrate having the movable body and the substrate having the fixed electrode 123 by the sealing material 125, the through-groove hole 126 is provided as in the present invention, and a further substrate is used. Sealing ensures sealing.

  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. The present invention is particularly effective for an electrostatic actuator or the like, but can also be applied to a case where a small opening between substrates is sealed.

Embodiment 7 FIG.
In the above embodiment, since the substrate having the fixed electrode is thicker and is a glass substrate, the through-slot hole 26 is formed on the substrate having the movable electrode such as the diaphragm 22. However, it is not particularly limited to this. The through-slot hole 26 may be formed in a direction that is easy to form in terms of configuration, process, and the like. In the first embodiment described above, the number of through-slot holes 26 is one. However, the present invention is not limited to this, and a plurality of through-slot holes and the like are formed as long as the sealing effect is not impaired. May be.

2 is an exploded view of a droplet discharge head according to Embodiment 1. FIG. It is sectional drawing of a droplet discharge head. 4 is a diagram illustrating a relationship between a through groove hole 26 and a lead portion 13 on 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 outline of the shape of a mask 60 and a joining board | substrate. 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 board | substrate, 11 Recessed part, 12 Individual electrode, 13 Lead part, 14 Terminal part, 15 Liquid intake port, 20 Cavity board | substrate, 21 Discharge chamber, 22 Diaphragm, 23 Insulating film, 24 Electrode extraction port, 25 Sealing material, 26 through-slot hole, 27 common electrode terminal, 28 reservoir, 29 orifice, 30 nozzle substrate, 31 nozzle hole, 32 diaphragm, 41 oscillation drive circuit, 42 wiring, 51 silicon substrate, 52 boron doped layer, 53 TEOS hard mask, 60 mask , 61 Mask opening, 62 Air release groove, 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, 122 movable body, 123 fixed electrode, 124 Fixed electrode terminal, 125 sealing material, 126 through-groove hole.

Claims (14)

One of the first substrate having a fixed electrode or the second substrate having a movable electrode that is opposed to the fixed electrode at a distance and operates by electrostatic force generated between the fixed electrode and the fixed electrode. Forming a through-slot hole for forming a sealing material for blocking a space formed between the movable electrode and the outside air from outside air within a desired range;
Attaching the mask substrate having the through-groove hole portion to the bonded substrate obtained by bonding the first substrate and the second substrate;
And a step of encapsulating the sealing material from the through groove to form a sealing portion on the bonding substrate. Before the step of attaching the mask substrate to the bonding substrate, the surface of the bonding substrate made of silicon in contact with the mask substrate and the mask substrate,
_{2. The} method of manufacturing an electrostatic actuator according to claim 1, further comprising a step of cleaning surfaces of the bonding substrate and the mask substrate that are in contact with each other by an O2 plasma method. Before the step of attaching the mask substrate to the bonding substrate, the surface of the bonding substrate made of silicon in contact with the mask substrate and the mask substrate,
_{2. The} method according to claim 1, further comprising a step of cleaning a surface of the bonding substrate in contact with the mask substrate by an O ₂ plasma method, and cleaning a surface of the mask substrate in contact with the bonding substrate with ammonia hydrogen peroxide. Manufacturing method of electrostatic actuator.   4. The method of manufacturing an electrostatic actuator according to claim 3, wherein a surface of the mask substrate that contacts the bonding substrate is washed with sulfuric acid / hydrogen peroxide instead of the ammonia / hydrogen peroxide.   5. The electrostatic according to claim 1, wherein a minute unevenness is provided on at least one of a surface of the bonding substrate in contact with the mask substrate and a surface of the mask substrate in contact with the bonding substrate. Actuator manufacturing method.   The method for manufacturing an electrostatic actuator according to claim 1, wherein the sealing material is sealed by a CVD method.   The method for manufacturing an electrostatic actuator according to claim 1, wherein the sealing material is sealed by a sputtering method.   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 method for manufacturing a droplet discharge head according to claim 8 is applied to manufacture a droplet discharge device.   A method for manufacturing an electrostatic device, wherein the device is manufactured by applying the method for manufacturing an electrostatic actuator according to claim 1.   An electrostatic actuator having a first substrate having a fixed electrode and a second substrate having a movable electrode that opposes the fixed electrode at a distance and operates by electrostatic force generated between the fixed electrode, A mask substrate having an opening corresponding to a through-groove hole for forming a sealing material for blocking a space formed between the fixed electrode and the movable electrode from outside air within a desired range.   The mask substrate according to claim 11, wherein silicon is used as a material.   13. The mask substrate according to claim 11 or 12, wherein a communication groove for communicating a recess formed in the electrostatic actuator and the outside is provided on a surface in contact with the electrostatic actuator. 14. The method for manufacturing a mask substrate according to claim 11, wherein the opening portion of the mask substrate according to claim 11 is formed by etching the substrate.

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