JP2007112075A - Electrostatic actuator, liquid droplet discharging head, liquid droplet discharging device and methods for manufacturing various electrostatic devices - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a surplus sealing medium removal process by making a sealing medium adhere only to a desired part. <P>SOLUTION: This method comprises the following processes: (1) a process to open a through slot 26 for arranging the sealing medium 25 to shut a gap 40 off an atmosphere, in one of the substrates (10) and (20) of a joint body 50, the joint body 50 being made up of the electrode substrate 10 with individual electrodes 12 and the cavity substrate 20 which is opposed to the electrode substrate 10 through the individual electrodes 12 and a gap 40, and has oscillating sheets 22 to be actuated by electrostatice force generated between the individual electrodes 12; (2) a process to cover a first masking substrate 60A with the open part corresponding to the through slot 26 by bringing the substrate 60A into close contact with the cavity substrate 20 with the formed through hole 26; (3) a process to cover the first masking substrate 60A by bringing a second masking substrate 60B with the open part corresponding to the open part of the first masking substrate 60A into close contact with the first masking substrate 60A; and (4) a process to seal the gap 40 by selectively accumulating the sealing medium 25 into the through slot 26 through utilizing the open parts of the second masking substrate 60B and the first masking substrate 60A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrostatic actuator in which a movable part is displaced by an electrostatic force to perform an operation, an electrostatic device such as a droplet discharge head to which the actuator is applied, an apparatus using the device, or a manufacturing method thereof.

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

In the electrostatic actuator as described above or a droplet discharge head using the electrostatic actuator, if moisture or the like adheres to at least one surface between the movable electrode (the vibration plate in the droplet discharge head) and the fixed electrode, There is a possibility that the electrostatic attraction characteristics may be deteriorated due to charging of polar molecules such as. 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 gap between the opposed surfaces of the movable electrode and the fixed electrode from the outside air. This gap can be almost closed by joining the movable electrode substrate and the fixed electrode substrate. However, if the gap is completely closed, it becomes difficult to supply power (charge) to the electrode from the outside. An opening for taking out the electrode is provided in the part. The opening portion is sealed with a sealing material to ensure electrical connection, and airtight sealing is performed to prevent intrusion of moisture or the like (see, for example, Patent Document 1).
JP 2002-1972

  As described above, when airtight sealing is performed by sealing the opening portion with a sealing material, for example, in the process of formation, the sealing material originally does not require sealing, for example, is bonded to another substrate. If it adheres to a portion or a portion to be a terminal of the extracted electrode, it becomes an obstacle to bonding or electrical connection with another substrate, causing bonding failure or connection failure. Therefore, in order to prevent these defects, it is necessary to further perform a process of removing excess sealing material. In the removal process, the sealing material is scraped off or washed, which increases the possibility of generation of foreign matter such as dust, and also reduces productivity.

  The present invention is for solving such problems, and eliminates an unnecessary sealing material removing step by attaching a sealing material only to a desired portion, thereby improving sealing efficiency and production efficiency. It is an object to provide an electrostatic actuator, a droplet discharge head, a droplet discharge apparatus, and an electrostatic device manufacturing method capable of performing the above.

  The method for manufacturing an electrostatic actuator according to the present invention includes: a first substrate having a fixed electrode; and a movable electrode that is opposed to the fixed electrode through a gap and operates by electrostatic force generated between the fixed electrode. Forming a through-slot hole for disposing a sealing material that blocks the gap from outside air on one substrate of the joined body joined to the second substrate, and a part corresponding to the through-slot hole A first mask substrate having an opening in contact with the substrate in which the through-groove hole is formed to cover the substrate, and a second mask substrate having a portion corresponding to the opening of the first mask substrate, The step of covering the first mask substrate by closely contacting the first mask substrate and the opening of the second mask substrate and the first mask substrate are used to selectively apply the sealing material to the through groove hole. Deposited in the gap And a step of stopping.

According to the present invention, a mask is formed by laminating a first mask substrate and a second mask substrate, and a sealing material is selectively deposited in the through-groove hole through these openings to seal the gap. Stop material can be efficiently deposited on an appropriate site. Therefore, it is possible to prevent adhesion of the fixed electrode to which the sealing material should not be attached to the contact point between the external power supply means and to prevent poor connection or to extend the life by reliable sealing. Can do. In addition, since the two mask substrates are stacked and the sealing material is deposited in the through-groove hole, the second mask substrate on the upper surface is warped due to the film stress of the sealing material. Since no sealing material is deposited, warping does not occur, and the sealing material can be prevented from wrapping around the joined body surface.
Each mask substrate is preferably manufactured from silicon. In the case of silicon, openings and grooves can be easily formed by etching.

  In addition, the method for manufacturing an electrostatic actuator according to the present invention is a movable substrate that is opposed to the first substrate having a fixed electrode through the gap and that is operated by electrostatic force generated between the fixed electrode. Forming a through slot for disposing a sealing material for blocking the gap from outside air on one substrate of the joined body joined to the second substrate having an electrode; and cutting the joined body. A plurality of mask pieces having a size corresponding to each actuator of the plurality of electrostatic actuators obtained in this manner and having openings corresponding to the through-slot holes are juxtaposed on the substrate on which the through-slot holes are formed. And a step of covering the substrate by closely contacting the substrate, and a step of sealing the gap by selectively depositing the sealing material in the through groove hole using an opening of the mask piece. .

  According to the present invention, a plurality of mask pieces having openings corresponding to the through-slot holes are used as masks, and a sealant is selectively deposited in the through-slot holes through the openings to seal the gap. Therefore, the sealing material can be efficiently deposited at an appropriate site. Therefore, it is possible to prevent adhesion of the fixed electrode to which the sealing material should not be attached to the contact point between the external power supply means and to prevent poor connection or to extend the life by reliable sealing. Can do. Also, since a plurality of mask pieces are juxtaposed and the sealing material is deposited in the through-groove holes, the mask piece warpage due to the film stress of the sealing material covers the entire substrate on which the through-groove holes are formed. Compared to the mask to be warped, the warpage due to the film stress of the sealing material is much smaller, and the sealing material can be prevented from wrapping around the bonded body surface.

It is preferable that the mask piece is positioned on the bonded body by passing the bonded body and the mask piece through a positioning pin. Thereby, the mask piece can be easily attached to the joined body.
The mask piece is preferably made of silicon. In the case of silicon, openings and grooves can be easily formed by etching.
Furthermore, it is preferable that the sealing material is deposited by a CVD method or a sputtering method. According to these, it is possible to easily deposit the sealing material selectively in the through groove hole.

The method for manufacturing a droplet discharge head according to the present invention forms a pressure fluctuation mechanism for collecting and discharging droplets by applying any one of the above-described electrostatic actuator manufacturing methods. According to this, it is possible to efficiently obtain a long-life droplet discharge head in which the gap between the electrodes of the pressure variation mechanism is appropriately sealed within a predetermined range.
The method for manufacturing a droplet discharge device of the present invention is a method for manufacturing a droplet discharge device by applying the method for manufacturing a droplet discharge head described above. Thereby, a long-life droplet discharge device can be obtained.
The method for manufacturing an electrostatic device according to the present invention forms a drive mechanism by applying any one of the above-described methods for manufacturing an electrostatic actuator. According to this, a long-life electrostatic device in which the gap between the electrodes of the drive mechanism is appropriately sealed within a predetermined range can be obtained efficiently.

Embodiment 1
FIG. 1 is an exploded perspective 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 the present embodiment, a face eject type liquid droplet ejection head will be described as a representative device using an electrostatic actuator driven by an electrostatic method, for example. (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 this embodiment includes three substrates: an electrode substrate 10 that is a first substrate, a cavity substrate 20 that is a second substrate, and a nozzle substrate 30 that is a third substrate. Are sequentially laminated and joined. In this embodiment, the electrode substrate 10 and the cavity substrate 20 are bonded by anodic bonding, and 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 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 recesses 11 (particularly at the bottom) so as to face the discharge chambers 21 (vibrating plates 22) of the cavity substrate 20, and the lead portions 13 and the terminal portions 14 are further provided. They are provided integrally (hereinafter, these are collectively described as individual electrodes 12 unless otherwise distinguished). A gap 40 (see FIG. 2) that can be displaced by bending the diaphragm 22 is formed between the diaphragm 22 and the individual electrode 12 due to 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 is 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 member 25 as described later. A through-slot hole 26 is formed to form a sealing portion that is deposited immediately above. Furthermore, on the lower surface of the cavity substrate 20 (surface facing the electrode substrate 10), an insulating film (here, Tetraethyl orthosilicate Tetraethoxysilane: tetraethoxysilane) for electrically insulating the diaphragm 22 and the individual electrode 12 is provided. the SiO ₂ of the TEOS film can be with (ethyl silicate)) 23 of plasma CVD (Chemical Vapor deposition: also referred to as TEOS-pCVD) method using, and 0.1μm film formation. The insulating film 23 may be made of Al ₂ O ₃ (aluminum oxide (alumina)) or the like. 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 12 to the diaphragm 22 from an external power supply means (not shown). An orifice 29 serving as a groove for communicating the discharge chamber 21 and the reservoir 28 is provided.

  The nozzle substrate 30 is made of, for example, a silicon substrate, and a plurality of nozzle holes 31 are formed. 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, it is expected to improve straightness when ejecting liquid droplets. Therefore, 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 28 as the diaphragm 22 bends.

  FIG. 2 is a cross-sectional view along the longitudinal direction of the individual electrode 12 of the droplet discharge head of FIG. In this embodiment, a high-concentration boron-doped layer that can be used as an electrode and can be used as an etching stop during etching is formed on a silicon substrate, and this is used as the diaphragm 22. The discharge chamber 21 provided with the vibration plate 22 on the bottom wall stores the liquid to be discharged from the nozzle hole 31, and is driven so that the vibration plate 22 serving as the bottom wall bends and displaces. And the droplets are ejected from the nozzle holes 31. The driving of the diaphragm 22 is performed by an electrostatic force generated by applying a voltage to the diaphragm 22 and the individual electrode 12. Therefore, the diaphragm 22 and the individual electrode 12 constitute an electrostatic actuator.

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 FPC (Flexible Print Circuit), and controls supply of an applied voltage. The oscillation drive circuit 41 oscillates at 24 kHz, for example, 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, for example, when an electric charge is supplied to the individual electrode 12 to be positively charged and the vibration plate 22 is relatively negatively charged, the vibration is attracted to the individual electrode 12 by the electrostatic force and bent. Mu 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.
In addition, the sealing material 25 is provided between the electrode substrate 10 and the cavity substrate 20 in order to block the gap 40 from the outside air and seal it so that foreign matter, moisture (water vapor) or the like does not enter the gap 40. Yes.

  FIG. 3 is a plan view showing 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, the through 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. As long as reliable sealing is possible, the width may be 300 μm (0.3 mm), for example. The sealing material 25 is made of silicon oxide (inorganic compound) that has high insulation and hermetic sealing ability and has resistance to acidic and alkaline solutions used for cleaning and the like. 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 be about 2 to 3 μm or more as long as the bonding with the nozzle substrate 30 is not affected.

A part of the gap 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), sputtering, or vapor deposition. Then, silicon oxide (SiO ₂ ) as the sealing material 25 is deposited to form a sealing portion, and the gap 40 is shut off from the outside air. As the sealing material 25, in addition to silicon oxide, for example, Al ₂ O ₃ (aluminum oxide (alumina)), silicon nitride (SiN), silicon oxynitride (SiON), Ta ₂ O ₅ (tantalum pentoxide), DLC (Diamond Like Carbon), polypalaxylylene, PDMS (polydimethylsiloxane: a kind of silicone rubber), inorganic or organic compounds such as epoxy resin, etc., have a relatively small molecular weight and can be deposited by vapor deposition, sputtering, etc. Substances that are impermeable to moisture can be used.

By the way, conventionally, an epoxy resin is applied to a portion (a portion of the terminal portion 14) opened between the electrode substrate 10 and the cavity substrate 20, and is cured to form a sealing portion. However, when using an epoxy resin, it is necessary to make the lead portion 13 sufficiently long so that it does not penetrate between the individual electrode 12 and the diaphragm 22 due to a capillary phenomenon or the like, which has been an obstacle to downsizing. In addition, 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 gap serving as the electrode outlet 24 is wide, even if a mask or the like is attached, the material wraps around. It has been 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 42, the terminal portion 14 and the wiring 42 cannot be electrically connected well, resulting in a connection failure (conduction failure). May occur.

  In order to prevent the above-mentioned connection failure, an extra step of removing the sealing material is necessary. However, this step not only consumes time but also causes the generation of 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 only the necessary location can be efficiently formed as a sealing portion. The hole 26 is opened. Further, a mask (described later) having an opening corresponding to the through-slot hole 26 is attached, and the sealing material 25 is deposited only on the bottom part of the through-slot hole 26 (immediately above the lead part 13) to form a sealed part. A specific method for doing this will be described in Example 1 and Example 2 for explaining the following method for manufacturing a droplet discharge head (including a method for manufacturing an electrostatic actuator).

Example 1
4 and 5 are a series of process diagrams showing manufacturing processes of the droplet discharge head according to the first embodiment. The droplet discharge head manufacturing process will be described with reference to FIGS. In practice, a plurality of droplet discharge head members are simultaneously formed for each wafer. FIGS. 4 and 5 show one unit of the droplet discharge head.

First, 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 / Under the conditions of min (100 sccm) and oxygen flow rate of 1000 cm ³ / min (1000 sccm), a TEOS insulating film 23 is formed to a thickness of 0.1 μm (FIG. 4A).

On the other hand, the electrode substrate 10 is manufactured in a separate process from the above (a). For example, etching or the like is performed on one surface of a glass substrate of about 1 mm to form the 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, the liquid intake 15 is formed by sandblasting or cutting.
Then, after heating the silicon substrate 51 and the electrode substrate 10 to 360 ° C., the negative electrode is connected to the electrode substrate 10 and the positive electrode is connected to the silicon substrate 51, and a voltage of 800 V is applied to perform anodic bonding. 10 is a bonded substrate (bonded body) 50 laminated with a gap 40 (FIG. 4B).

  The surface of the bonding substrate 50 is ground until the silicon substrate 51 has a thickness of about 60 μm. 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 53 (hereinafter referred to as TEOS hard mask) 53 formed by TEOS is formed on the surface of the bonding substrate 50 on which wet etching has been performed 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. Good.

  Next, the bonding substrate 50 is immersed in a 35 wt% potassium hydroxide aqueous solution, and anisotropic wet etching (hereinafter, referred to as “unetching wet etching”) is performed until the thicknesses of the discharge chamber 21, the through groove 26, and the electrode outlet 24 become about 10 μm. , Referred to as wet etching). Further, the bonded substrate 50 is immersed in a 3 wt% concentration potassium hydroxide aqueous solution, and the boron doped layer 52 is exposed, and wet etching is continued until it is determined that an etching stop at which the progress of etching is extremely slow has been effective (see 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 50 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 having an opening in the portion that becomes the through groove hole 26 and the electrode extraction port 24 is used as the silicon substrate 51 of the bonding substrate 50. Attach to the side 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 to only the portion that becomes the electrode outlet 24 to open it and communicate with the gap 40 (FIG. 5G). Here, for example, in order to increase the alignment accuracy between the bonding substrate 50 and the mask, the silicon mask may be mounted by pin alignment in which pins are passed through the bonding substrate 50 and the silicon mask. Here, the opening is formed by anisotropic dry etching, but the boron doped layer 52 may be broken by protruding with a pin or the like.

Subsequently, the gap 40 formed between the cavity substrate 20 (silicon substrate 51 on which the flow path is formed) and the individual electrode 12 of the electrode substrate 10 is sealed. Prior to this sealing, a first mask substrate 60A and a second mask substrate 60B are manufactured using a silicon substrate, preferably a silicon substrate having a crystal orientation (100). Specifically, the first mask substrate 60A having an opening corresponding to the through groove hole 26 and the second mask substrate 60B having an opening corresponding to the opening of the first mask substrate 60A are processed by wet etching. Manufactured. The first mask substrate 60A is provided with an opening as a mask opening 61A and a V-shaped cross-sectional groove as an atmosphere opening groove 62A, and an opening as a mask opening 61B is formed in the second mask substrate 60B. .
Then, the first mask substrate 60A is placed on the cavity substrate 20 in which the through-groove holes 26 are formed, and the second mask substrate 60B is further disposed on the cavity substrate 20 in correspondence with the mask openings 61A and 61B. Laminate as shown in (h). Thus, the cavity substrate 20 is covered (masked) by the first mask substrate 60A, and the first mask substrate 60A is covered (masked) by the second mask substrate 60B. Then, the outer peripheral portions of the bonding substrate 50 and the second mask substrate 60B are sandwiched and fixed together with a jig or the like. At this time, the space serving as the discharge chamber 21 and the space serving as the reservoir 28 are opened to the atmosphere by the atmosphere opening groove 62A provided in the first mask substrate 60A.

FIG. 6 is a diagram schematically showing the shapes of the first mask substrate 60A and the bonding substrate 50. As shown in FIG. 6A shows a surface where the first mask substrate 60A is in contact with the bonding substrate 50, and FIG. 6B shows a side surface of the first mask substrate 60A. FIG. 6C shows the side surface of the cavity substrate 20 of the corresponding bonded substrate 50. Here, a schematic shape of two rows of droplet discharge heads is described, but more rows are formed on an actual substrate (wafer), and the droplet discharge heads (chips) in each row are formed. There are many more.
The material of the first mask substrate 60A is not particularly limited, and the first mask substrate 60A may be made of a metal such as chromium. However, the material of the first mask substrate 60A is silicon that can easily produce a highly accurate mask using an etching process. preferable. The first mask substrate 60A is patterned on the silicon substrate so as to correspond to the portion of the through-groove hole 26 of the bonding substrate 50, and wet etching is performed with, for example, a hydrofluoric acid aqueous solution to form the opening 61A and the air opening groove 62A. Form. Here, the opening and the air opening groove are formed by wet etching, but may be formed by dry etching, for example. Note that the opening portion on the surface side of the opening 61A of the first mask substrate 60A that is in contact with the bonding substrate 50 has a through groove 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 make it smaller than the opening of the hole 26.

The bonding substrate 50 in which the first mask substrate 60A and the second mask substrate 60B are closely stacked is put in a CVD apparatus, and, for example, SiO ₂ is formed as the sealing material 25. At this time, the sealing material 25 is selectively deposited only in the through groove hole 26 by the first and second mask substrates 60A and 60B, and the gap 40 formed between the individual electrode 12 and the diaphragm 22 is sealed. Stopped. Since SiO ₂ is formed on the second mask substrate 60B, the second mask substrate 60B is warped by the film stress, but the first mask substrate covered by the second mask substrate 60B is used. In 60A, no SiO ₂ film is formed and no warpage occurs. That is, since the sealing material SiO ₂ is formed in a state in which the adhesion between the first mask substrate 60A and the bonding substrate 50 is ensured, the SiO ₂ does not wrap around the terminal portion 14 of the individual electrode 12, etc. The sealing material 25 can be deposited only on a desired sealing portion.
As the sealing material 25, SiN, SiON, Al ₂ O ₃ or the like can be used in addition to SiO ₂ .

  After the sealing process described above, the first and second mask substrates 60A and 60B are removed from the bonding substrate 50. Thereafter, for example, sputtering is performed using platinum (Pt) as a target to form the common electrode terminal 27. Further, the nozzle substrate 30 is bonded and bonded to the cavity substrate 20 of the bonding substrate 50 (FIG. 5I). Further, dicing is performed along the dicing line, and the liquid droplet ejection head is cut into individual liquid droplet ejection heads to complete the liquid droplet ejection head. Thereafter, a flexible printed circuit (FPC) on which the driver IC is mounted is joined to the terminal portion 14 of the individual electrode 12 using an anisotropic conductive adhesive (ACF) or the like. Since there is no deposition of the sealing material 25, conduction can be achieved without problems.

In the case of an electrostatic actuator that is not applied to the droplet discharge head, it is not necessary to form a flow path such as the discharge chamber 21 and the reservoir 28 in the silicon substrate 51 in the above process, and the nozzle substrate 30 is bonded. Is also unnecessary.
According to the first embodiment described above, the through-groove hole 26 is provided in the cavity substrate 20, the cavity substrate 20 is covered with the first mask substrate 60 </ b> A and the second mask substrate 60 </ b> B, and each opening corresponding to the through-groove hole 26. The sealing material 25 such as SiO ₂ can be selectively deposited only on the portion directly above the lead portion 13 using 61A and 61B. As a result, a sealing portion can be efficiently formed only at a necessary portion, and the gap 40 formed at the facing portion of the diaphragm 22 and the individual electrode 12 can be easily blocked from the outside air. Moreover, since it is not necessary to perform the process of removing the excess sealing material 25 as in the prior art, a connection failure can be prevented without impairing the electrical connection with the wiring or the like. Furthermore, since the sealing material 25 is deposited by sputtering, CVD, vapor deposition or the like, the sealing process can be reliably performed on a plurality of wafers at once, and the manufacturing efficiency can be improved.

Example 2
In the second embodiment, in the manufacturing process of the droplet discharge head shown in FIGS. 4 and 5, the mask used in the sealing process of FIG. . Here, instead of the first mask substrate 60A and the second mask substrate 60B of the first embodiment, the through groove hole 26 forms a plurality of mask pieces 70 having portions corresponding to the through groove holes 26 opened as openings 70A. The sealing material 25 is selectively deposited in the through-groove hole 26 while being juxtaposed to the cavity substrate 20 and in close contact with the cavity substrate 20.

FIG. 7 is an explanatory diagram illustrating a bonding substrate masking method according to the second embodiment. FIG. 7 shows an example in which nine droplet discharge heads are manufactured using a silicon wafer that is a material to be the cavity substrate 20, and FIGS. 7A and 7B show the bonding substrate 50. A plan view and a side sectional view (center longitudinal sectional view) in a state where a plurality of mask pieces 70 are mounted are shown.
Here, a silicon substrate, for example, a silicon substrate having a crystal orientation (100) is processed by wet etching, and a mask opening 70A having a portion corresponding to the through groove hole 26 opened, a through hole 70B for a positioning pin, and air release A mask substrate having a V-shaped cross-sectional groove formed as a groove (corresponding to the air opening groove 62A in FIG. 6) is manufactured. This mask substrate is basically the same as the first mask substrate 60A shown in FIG. Subsequently, the mask substrate is divided into a plurality of pieces. Here, the first mask substrate 60A is formed by dicing so as to have a shape equivalent to or slightly larger than each unit of nine electrostatic actuators (or droplet discharge heads) made from one silicon wafer. A corresponding mask substrate is cut to prepare a plurality of mask pieces 70. Below, the sealing method of the gap part using this mask piece 70 is demonstrated.

  First, the bonded substrate 50 is set through the positioning pins 72 on the wafer setting jig 73 provided with the positioning pins 72. Subsequently, a plurality of mask pieces 70 are juxtaposed on the cavity substrate 20 of the bonding substrate 50 through the positioning pins 72. Further, a protective mask 71 is disposed on the outer peripheral portion of the outermost outline of the mask piece 70. Thus, each droplet discharge head region of the cavity substrate 20 is covered (masked) by the mask pieces 70, and the outer peripheral portion of the cavity substrate 20 is covered (masked) by the protective mask 71. At this time, the space serving as the discharge chamber 21 and the space serving as the reservoir 28 are opened to the atmosphere by the atmosphere opening groove provided in the mask piece 70.

Next, the bonding substrate 50 in which the mask piece 70 and the protective mask 71 are in close contact with each other is put in a CVD apparatus, and for example, SiO ₂ is formed as the sealing material 25. At this time, the sealing piece 25 is selectively deposited only in the through groove hole 26 by the mask piece 70, and the gap 40 formed between the individual electrode 12 and the diaphragm 22 is sealed. At this time, the sealing material 25 is deposited only on the bottom portion of the through groove hole 26 by the mask piece 70, and is not deposited on the terminal portion 14 of the individual electrode 12. In addition, since the mask piece 70 is smaller in size than the mask substrate before cutting, it is possible to suppress warping caused by film stress when the SiO ₂ film is formed. As a result, the SiO ₂ film is formed in a state in which the adhesion between the mask piece 70 and the bonding substrate 50 is ensured, so that the SiO ₂ does not wrap around the terminal portions 14 of the individual electrodes 12 and the desired sealing portion. Only the sealing material 25 can be deposited.

According to the second embodiment, the through hole 26 is provided in the cavity substrate 20, and the cavity substrate 20 is covered with the mask piece 70 in a form in which the first mask described in the first embodiment is divided into a plurality of portions. The sealing material 25 such as SiO ₂ can be selectively deposited only on the portion directly above the lead portion 13 from the opening of the mask piece 70 corresponding to the above. As a result, the sealing portion can be efficiently formed only at an appropriate portion, and the gap formed at the facing portion of the diaphragm 22 and the individual electrode 12 can be easily blocked from the outside air. Moreover, since it is not necessary to perform the process of removing the excess sealing material 25 as in the prior art, a connection failure can be prevented without impairing the electrical connection with the wiring or the like. Furthermore, since the sealing material 25 is deposited by sputtering, CVD, vapor deposition or the like, the sealing process can be reliably performed on a plurality of wafers at once, and the manufacturing efficiency can be improved.
The electrostatic actuator or the droplet discharge head can be manufactured by adopting the second embodiment instead of the sealing process of the first embodiment and adopting the same processes as the first embodiment for the other processes.

Embodiment 2
FIG. 8 is a schematic configuration diagram of an ink jet printer which is a droplet discharge device using the droplet discharge head manufactured in the first embodiment. 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 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 acid, etc.) A liquid containing a probe such as a protein may be discharged. In addition, it can be used for discharging dyes such as cloth.

Embodiment 3
FIG. 9 is a diagram showing a wavelength tunable optical filter using the present invention. Embodiment 2 is an example in which an electrostatic actuator is applied to a droplet discharge head, but the electrostatic actuator of the present invention is not limited to a droplet discharge head, and can be applied to a drive unit of another device. . 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, the fixed electrode terminal 124 is taken out to supply charges to the fixed electrode. At that time, in order to ensure an airtight seal 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 another substrate is used. Sealing ensures sealing.

  Similarly, the formation of the sealing portion described above is also applied to other types of microfabricated actuators, pressure sensors, etc. such as motors, sensors, resonator elements such as SAW filters, tunable optical filters, mirror devices, etc. can do. 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 4
In each of the above-described embodiments, since the substrate having the fixed electrode is thicker and is a glass substrate, the through-slot holes 26 and 126 are provided toward the substrate having a movable electrode such as the diaphragm 22. However, the present invention is not limited to this. What is necessary is just to make it form a through-slot hole in the direction which is easy to form on structure, a process, etc. Moreover, you may form arbitrary arbitrary multiple through-slot holes 26 in the range which does not impair the sealing effect.

FIG. 3 is an exploded perspective view of the droplet discharge head according to the first embodiment. Sectional drawing of a droplet discharge head. The top view showing the relationship between a through-slot hole and the lead part on an electrode substrate. FIG. 5 is a process diagram illustrating a manufacturing process of the droplet discharge head according to the first embodiment. FIG. 5 is a process diagram illustrating a manufacturing process continued from FIG. 4. FIG. 3 is an explanatory diagram of shapes of a mask substrate and a bonding substrate according to the first embodiment. FIG. 6 is an explanatory diagram illustrating a bonding substrate masking method according to a second embodiment. FIG. 4 is a configuration diagram of a droplet discharge device according to a second embodiment. FIG. 6 is a configuration diagram of a wavelength tunable optical filter according to a third embodiment.

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-groove hole, 27 common electrode terminal, 28 reservoir, 29 orifice, 30 nozzle substrate, 31 nozzle hole, 32 diaphragm, 40 gap, 41 oscillation drive circuit, 42 wiring, 50 bonded substrate, 51 silicon substrate, 52 boron doped layer, 53 TEOS hard mask, 60A first mask substrate, 60B second mask substrate, 61A opening, 61B opening, 62 air release groove, 101 drum, 102 droplet discharge head, 120 movable mirror, 121 fixed mirror, 122 movable body , 123 fixed electrode, 124 fixed electrode terminal, 125 sealing material, 126 through-groove hole.

Claims (10)

A bonded body in which a first substrate having a fixed electrode and a second substrate having a movable electrode facing the fixed electrode through a gap and operating with an electrostatic force generated between the fixed electrode and the fixed electrode are bonded. Forming a through slot for disposing a sealing material for blocking the gap from outside air on one of the substrates;
A first mask substrate having an opening corresponding to the through-slot hole is attached to the substrate on which the through-slot hole is formed to cover the substrate;
Covering the first mask substrate with a second mask substrate having an opening corresponding to the opening of the first mask substrate in close contact with the first mask substrate;
Using the openings of the second mask substrate and the first mask substrate to selectively deposit the sealing material in the through-groove holes to seal the gap;
A method for manufacturing an electrostatic actuator, comprising:   2. The method of manufacturing an electrostatic actuator according to claim 1, wherein each of the mask substrates is made of silicon. A bonded body in which a first substrate having a fixed electrode and a second substrate having a movable electrode facing the fixed electrode through a gap and operating with an electrostatic force generated between the fixed electrode and the fixed electrode are bonded. Forming a through slot for disposing a sealing material for blocking the gap from outside air on one of the substrates;
A plurality of mask pieces having a size corresponding to each actuator of a plurality of electrostatic actuators obtained by cutting the joined body and having openings corresponding to the through-slot holes are formed in the through-slot holes. A step of juxtaposing a plurality of substrates on the substrate and closely contacting the substrate to cover the substrate;
Utilizing the opening of the mask piece to selectively deposit the sealing material in the through-groove hole and seal the gap;
A method for manufacturing an electrostatic actuator, comprising:   4. The method of manufacturing an electrostatic actuator according to claim 3, wherein the bonded body and the mask piece are passed through a positioning pin to position the mask piece on the bonded body.   5. The method of manufacturing an electrostatic actuator according to claim 3, wherein the mask piece is made of silicon.   The method for manufacturing an electrostatic actuator according to claim 1, wherein the sealing material is deposited by a CVD method.   The method for manufacturing an electrostatic actuator according to claim 1, wherein the sealing material is deposited by a sputtering method.   A method for manufacturing a droplet discharge head, comprising applying the method for manufacturing an electrostatic actuator according to claim 1 to form a pressure fluctuation mechanism for storing and discharging droplets.   A method for manufacturing a droplet discharge device, wherein the method for manufacturing a droplet discharge head according to claim 7 is applied to manufacture a droplet discharge device. A method for manufacturing an electrostatic device, wherein the drive mechanism is formed by applying the method for manufacturing an electrostatic actuator according to claim 1.

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