JP2003034035A - Liquid drop discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the trouble that joining at low temperatures is impossible. SOLUTION: A silicon oxide film 11 is formed on a surface at the side of a second substrate 2 of a first substrate 1 where a diaphragm 10 is set, and a splicing part 13 to be joined to the first substrate 1 is set to the side of the second substrate 2 where an electrode 15 is set. At least a surface at the side of a splicing face of the splicing part 13 is formed of silicon, and the first substrate 1 and the second substrate 2 are joined by directly joining the silicon oxide film and the silicon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head,
In particular, it relates to an electrostatic droplet discharge head.

[0002]

2. Description of the Related Art As an ink jet head used in an ink jet recording apparatus used as an image recording apparatus such as a printer, a facsimile, a copying machine or an image forming apparatus, a nozzle for ejecting an ink droplet and an ejection chamber (ink flow) communicating with the nozzle. Channel, ink chamber, pressure chamber, liquid chamber,
It is also called a pressurizing chamber or a pressurizing liquid chamber. ), A vibration plate forming the wall surface of the discharge chamber, and an electrode facing the vibration plate, the vibration plate is deformed by an electrostatic force to change the pressure / volume in the discharge chamber, and the ink is ejected from the nozzle. An electrostatic droplet discharge head that discharges droplets is known.

As the droplet discharge head, for example, a droplet discharge head for discharging a liquid resist as droplets, DN
There is also a droplet discharge head that discharges the sample A as droplets, but in the following, an inkjet head will be mainly described. Further, in such an electrostatic droplet discharge head, a diaphragm serving as a movable portion and an electrode facing the diaphragm constitute an electrostatic actuator. In addition to the inkjet heads described above, it is also used in micropumps, microswitches (microrelays), multi-optical lens actuators (micromirrors), microflow meters, pressure sensors, etc. explain.

In the electrostatic ink jet head,
The mechanical deformation characteristics of the diaphragm greatly affect the ink droplet ejection characteristics, and it is necessary to reduce the diaphragm thickness and control it with high accuracy.Therefore, a high-concentration boron diffusion layer is formed on the silicon substrate. By anisotropically etching a silicon substrate using the boron diffusion layer as an etching stop layer, a thin film diaphragm with high precision is formed.

Further, in the electrostatic ink jet head, it is necessary to control the distance between the diaphragm and the electrodes, that is, the gap size with extremely high precision. Therefore, for example, a substrate for forming the diaphragm and a substrate for forming the electrodes are used. In the case of using a silicon substrate, a direct bonding method, which is used for manufacturing an SOI (silicon-on-insulator) wafer and can obtain a strong and reliable bonding force, is used for bonding. Further, for example, a silicon substrate is used as a substrate for forming a diaphragm, and a glass substrate is used as an electrode for forming electrodes to perform anodic bonding.

For example, in Japanese Patent Laid-Open No. 6-71882, a nozzle hole for ejecting ink droplets, an ejection chamber communicating with the nozzle hole, a diaphragm on the bottom wall of the ejection chamber, and a diaphragm opposed to the diaphragm. A vibration chamber is provided with an electrode that is driven by an electrostatic force, and a concave portion for a vibration chamber or an electrode is mounted on one or both of the anodic bonding surfaces of the substrate that forms the vibration plate and the substrate that forms the electrode. It is described that the gap length G between the vibrating plate and the electrode is set to 0.05 to 2.0 by forming a concave portion for use, a silicon oxide film or the like.

Japanese Unexamined Patent Publication (Kokai) No. 6-23986 discloses a first silicon substrate in which a nozzle and a cavity to be a pressure chamber are formed and a second silicon substrate which serves as a vibrating plate. It is described that the above silicon substrate and the second silicon substrate on which a high-concentration p-type silicon layer is formed are bonded to each other by a direct silicon-silicon bonding method.

In Japanese Unexamined Patent Publication No. 9-267479, a high-concentration p-type silicon layer of a first silicon substrate having a high-concentration p-type silicon layer formed on one side thereof is opposed to a second silicon substrate having a nozzle formed thereon. At the same time, it is described that the vibration plate is formed by direct bonding with a temperature rising rate from room temperature of 5 ° C./minute or less.

In Japanese Unexamined Patent Publication No. 9-286101, a sodium silicate aqueous solution containing silicon oxide and Na ₂ O and water is diluted on the bonding surface of a silicon wafer having a nozzle, and a sodium silicate layer is formed by spin coating. And the silicon wafer on which the vibration plate is formed are bonded immediately after the formation, a load is applied from the opposite side of the bonding surface, and heating is performed in the air at 800 ° C. or higher and 200 ° C. or lower to bond them. Obtaining a wafer is described.

Japanese Unexamined Patent Publication No. 10-286954 discloses that
After cleaning and drying the first silicon substrate and the second silicon substrate, a polysilazane layer is formed on the bonding surface side of the first silicon substrate by spin coating, and immediately after forming the polysilazane layer, the first and second silicon substrates are formed. It is described that a silicon wafer is bonded and a bonded wafer is obtained by applying a load from the side opposite to the bonding surface and heating it in the air at 450 ° C. for 1 hour.

[0011]

In an electrostatic ink jet head, a voltage is applied to a borosilicate glass substrate provided with an electrode as described above and a silicon substrate provided with a vibrating plate under heating to bond them together. When the anodic bonding method described above is used, the substrates, which have a difference in thermal expansion of borosilicate glass and silicon, are bonded to each other, and therefore, the bonding stress is likely to be applied to the diaphragm, and variations in vibration characteristics are likely to occur.

Further, in the case of performing anodic bonding, due to the above-mentioned stress, a manufacturing method using a large substrate such as a wafer process cannot be adopted, and furthermore, the substrate contains glass containing alkali ions and a conductive substrate. Depending on the conditions, the problem of contamination with alkali metal may occur,
When a high voltage of 100 to 2000 V is applied at a temperature of about 0 ° C., problems such as stress accumulation on the diaphragm occur.

Therefore, as described above, the direct bonding method for directly bonding the wafers is adopted. However,
In electrostatic force driving, it is necessary to form a highly reliable insulating film on the individual electrodes and the diaphragm in order to prevent short circuits between electrodes, protect the contact surface, and enhance drive reliability.
Usually, an insulating film using an oxide film such as a silicon oxide film is formed.

In the joining using this direct joining, the temperature required for obtaining a reliable joining greatly differs depending on the joining surface. It is a silicon-silicon bond that can be bonded at the lowest temperature. Then, the silicon oxide film and the silicon are continuously joined, and these junctions are performed at 800 ° C to 1100 ° C.
It can be used at a moderate joining temperature. On the other hand, in the bonding of the silicon oxide film and the silicon oxide film, the bonding between the interfaces is extremely stable, so that bonding at 1200 ° C. or higher is required to obtain reliable bonding.

By the way, when the substrate on which the diaphragm is formed and the substrate on which the electrode is formed are directly joined as described above, the heat resistance of the substrate on which the electrode is formed and the high concentration boron diffusion on the diaphragm as described above. When a layer is used, the redistribution of boron directly affects the thickness of the diaphragm and its variation, so that the bonding temperature is preferably low.

Therefore, as described above, water glass (sodium silicate solution) is used to bond the two substrates in order to lower the bonding temperature. This material has good bonding properties at low temperatures. However, since the water content is high, the influence of the gas (water vapor etc.) emitted from the film is unavoidable. Although polysilazane is also used for joining both substrates, this is excellent in reliability, but still has a problem of gas emission.

The present invention has been made in view of the above problems, provides high drive reliability, does not require pattern matching when bonding two substrates, and is lower in temperature than the bonding of oxide films. An object is to provide a droplet discharge head that can be joined.

[0018]

In order to solve the above problems, a droplet discharge head according to the present invention is provided with a vibrating plate.
A silicon oxide film is formed on the second substrate side surface of one substrate,
A bonding portion for bonding the first substrate is provided on the side of the second substrate on which the electrode is provided, and at least the bonding surface side surface of the bonding portion is formed of silicon, and the first substrate and the second substrate are bonded to the silicon oxide film. It is joined by direct joining with the silicon of the part.

Here, the second substrate is formed of a single crystal silicon substrate, and by digging the single crystal silicon substrate, it is possible to form a bonding portion in which at least the bonding surface side surface is made of silicon.

Further, it is possible to dispose the electrodes on the insulating film provided on the second substrate and to provide the bonding portion having at least the bonding surface side surface made of silicon on the insulating film. In this case, the electrodes are preferably made of single crystal or polycrystalline silicon. Further, the bonding portion of the second substrate can be formed from the member forming the electrode. Furthermore,
The bonding portion of the second substrate can be formed of single crystal or polycrystalline silicon provided over an insulating film that protects the electrodes.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an inkjet head according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 is an exploded perspective view of the head, FIG. 2 is a top view of the head without a nozzle plate, FIG. 3 is a cross-sectional view of the head in a longitudinal direction of a diaphragm, and FIG. 4 is a vibration of the head. It is a principal part expanded sectional explanatory view of a board short direction.

This ink jet head has a channel substrate 1 which is a first substrate using a single crystal silicon substrate and an electrode which is a second substrate which is provided below the channel substrate 1 and which uses a single crystal silicon substrate. It has a structure in which a substrate 2 and a nozzle plate 3 which is a third substrate provided on the upper side of the flow channel substrate 1 are laminated, and a plurality of nozzles 4 for ejecting ink droplets and an ink flow channel communicating with each nozzle 4 are formed. A certain liquid chamber 6 and a common liquid chamber 8 that communicates with each liquid chamber 6 via a fluid resistance portion 7 that also serves as an ink supply path are formed.

A plurality of liquid chambers 6 in which the nozzles 4 communicate with the flow path substrate 1 and a vibrating plate 1 forming a bottom portion which is a wall surface of the liquid chambers 6.
A concave portion for forming 0 (also serving as an electrode) is formed. Then, a silicon oxide film (SiO ₂ film) 11 for preventing a short circuit between electrodes is formed on the entire surface of the vibrating plate 10 of the flow path substrate 1 in the out-of-plane direction (electrode substrate 2 side).

Here, the flow path substrate 1 is, for example, (110)
When a plane-oriented single crystal silicon substrate is used, a high-concentration p-type impurity (for example, boron) is injected in advance into the thickness of the diaphragm to form a high-concentration boron diffusion layer that serves as an etching stop layer, and is bonded to the electrode substrate 2. After that, KO the concave portion that becomes the liquid chamber 6
By anisotropically etching using an alkaline etching solution such as an aqueous H solution, the high-concentration boron diffusion layer serves as an etching stop layer at this time (the etching rate becomes extremely small), and the diaphragm 10 is formed with high accuracy. To be done. As the high-concentration P-type impurity, there are gallium, aluminum, and the like in addition to boron, but boron is common in the semiconductor field.

Further, the flow path substrate 1 is an SOI (Silic) substrate in which a base substrate and an active layer substrate are bonded together via an oxide film.
It is also possible to use an on On Insulator) substrate.
Currently, for the purpose of manufacturing high-performance semiconductor devices,
A wafer having a silicon active layer of about 3 μm (this active layer is used for the diaphragm 10 in an inkjet head) can be easily obtained, and the cost can be reduced.

A single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 2, and an electrode forming recess 12 is formed by digging into the electrode substrate 2, and at a portion other than this electrode forming recess 12. By forming the joint portion (spacer portion) 13 that is joined to the flow path substrate 1, the joint portion 1
The surface of the bonding surface 3 of the bonding surface is made of silicon.

Then, an insulating film (silicon oxide film: SiO ₂ film, etc.) 14 for ensuring insulation from the electrode substrate 2 is formed on the bottom surface of the electrode forming recess 12, and a diaphragm is formed on the insulating film 14. The electrodes 15 facing each other are formed at a predetermined gap 16 with respect to the diaphragm 10.
And constitute an electrostatic actuator that deforms the vibration plate 10 by electrostatic force. Then, a silicon oxide film 17 serving as an electrode protective film is formed on the surface of the electrode 15.

Here, the electrode 15 is, for example, a two-layer structure of a tungsten side film and a polysilicon film, or Ti, T
A refractory metal such as iN or a polycrystalline silicon film doped with impurities can also be used. This electrode 15 is extended to the outside to form an electrode pad portion 15a.
An FPC cable in which a driver IC 19 which is an electrode head drive circuit is mounted on 5a by wire bonding or the like is connected through an anisotropic conductive film or the like.

An ink intake port 20 for supplying ink to the common liquid chamber 8 is formed in the electrode substrate 2. By bonding and connecting an ink supply pipe to the ink intake port 20, the common liquid chamber 8, the liquid chamber 6 and the like can be filled with ink supplied from an ink tank (not shown) through the ink intake port 20. It will be possible. The ink to be used is prepared by dissolving or dispersing a surfactant such as ethylene glycol and a dye or pigment in a main solvent such as water, alcohol or toluene. further,
If a heater or the like is attached to the inkjet head, hot melt ink can also be used.

On the nozzle plate 3, a large number of nozzles 4 are formed, and a groove portion is formed which forms a fluid resistance portion 7 for connecting the common liquid chamber 8 and the liquid chamber 6. Here, a water-repellent film is formed on the ink ejection surface (nozzle surface side). The nozzle plate 3 includes a glass substrate, a plastic plate, stainless steel or Kovar (Fe29-Ni-17).
A metal plate such as Co) or a silicon substrate can be used.

Then, the flow path substrate 1 and the electrode substrate 2 are bonded by direct bonding of silicon. In this case, the diaphragm 10
The silicon oxide film 11 is formed on the surface of the flow path substrate 1 which is the first substrate on which the electrode substrate 2 which is the second substrate is formed.
A joint portion (spacer portion) 13 that is joined to the flow path substrate 1 is provided on the side of the electrode substrate 2 on which 5 is provided, and at least the joint surface side surface of the joint portion 13 is formed of silicon (the electrode substrate 2 itself is silicon. Therefore, the surface of the bonding portion 13 on the bonding surface side is also made of silicon), and the flow path substrate 1 and the electrode substrate 2 are bonded by direct bonding of the silicon oxide film 11 and the silicon of the bonding portion 13.

The operation of the thus constructed ink jet head will be briefly described. The vibrating plate 10 serves as a common electrode and the electrode 15 serves as an individual electrode.
By applying a driving waveform from the driver IC 19 between the diaphragm 10 and the electrode 15, an electrostatic force (electrostatic attraction force) is generated between the diaphragm 10 and the electrode 15, and the diaphragm 10 is deformed and displaced toward the electrode 15. As a result, the internal volume of the liquid chamber 6 is expanded and the internal pressure is lowered, so that the liquid chamber 6 is filled with ink via the fluid resistance portion 7.

Next, when the voltage application to the electrode 15 is cut off,
The electrostatic force stops acting, and the diaphragm 10 is restored by its own elasticity. With this operation, the internal pressure of the liquid chamber 6 rises, and ink droplets are ejected from the nozzle 4. When voltage is applied to the electrodes again, the diaphragm 1 is again attracted by electrostatic attraction.
0 is drawn to the electrode 15 side. Therefore, the diaphragm 1
By applying a drive voltage between 0 and the electrode 15 according to the recorded image, ink droplets can be ejected according to the recorded image.

In this head, the bonding surface on the electrode substrate side is a single crystal or polycrystalline silicon layer on the bonding surface with the flow channel substrate, and the flow channel substrate provided with the vibrating plate and the electrode substrate provided with the electrode are Are bonded by direct bonding of SiO ₂ —Si. As a result, a protective film is formed on the gap side surface of the diaphragm.
Since (SiO ₂₎ is formed higher drive reliability is obtained, the bonding surface of the channel substrate and the electrode substrate, SiO ₂
Since it is made of -Si, direct bonding is possible at a firing temperature of 800 to 1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

Next, the manufacturing process of the ink jet head according to the first embodiment will be described with reference to FIGS. As shown in FIG. 5A, in order to prepare a single crystal or polycrystalline silicon substrate 31 to be the electrode substrate 2 and to form the concave portion 12 and the joint portion (spacer portion) 13 on this silicon substrate 31 by photolithography. The resist pattern is formed, and the recess 12 is formed by dry etching with HBr, Cl, CF ₄ , SF ₆ gas or the like, and the portion other than the recess 12 is used as the joint portion 13. The side surface is formed of single crystal or polycrystalline silicon, and after removing the resist, O ₂ plasma ashing is performed.

Then, as shown in FIG. 7B, after wafer cleaning (RCA cleaning or the like) is performed, thermal oxidation or the like is performed to form an insulating film 32 having a thickness of about 5000 angstroms. An electrode material 33 such as TiN, polysilicon, or tungsten silicide is formed on the surface. After that, as shown in FIG. 3C, a resist pattern corresponding to the electrode pattern is formed on the electrode material 33 by photolithography or the like, and the electrode material 3 is made of Cl-based gas or F-based gas.
3 is dry-etched to form the electrode 15, and after removing the resist, O ₂ plasma ashing is performed.

Next, as shown in FIG. 6A, after the wafer cleaning (RCA cleaning or the like) is performed, the electrode 1 is formed on the insulating film 32.
5 CV the silicon oxide film (SiO ₂ ) 34 including the surface
After the film is formed by the D method or the like, a pattern 3 for removing the oxide film 34 and the insulating film 32 on the substrate bonding surface by photolithography while leaving the electrode protection portion as shown in FIG.
5 is formed.

Then, as shown in FIG.
By wet etching or dry etching with CHF ₃ + CF ₄ gas to form the oxide film 3 on the substrate bonding surface or the like.
4 is removed to form the insulating film 17 for protecting the electrode, and then the insulating film 14 of the silicon substrate 31 is removed by etching (depending on the material, continuous treatment with etching of the electrode protective film is also possible) to form the electrode substrate 2. After forming the insulating film 14 between the electrodes 15 and removing the resist, O ₂ plasma ashing is performed to obtain the electrode substrate 2 provided with the electrodes 15 and the like.

Next, as shown in FIG. 7A, a silicon substrate 4 to be a channel substrate having a high-concentration boron diffusion layer 1a to be a vibration plate and a silicon oxide film 11 formed on the surface thereof.
1 is obtained, and the silicon substrate 41 and the electrode substrate 2 are washed with a mixed aqueous solution of ammonia and hydrogen peroxide as a pre-bonding pretreatment, and then the silicon substrate 41 and the electrode substrate 2 are cleaned.
And are joined directly.

After that, a liquid chamber pattern is formed on the silicon substrate 41 by photolithography or the like, and the silicon substrate 41 is etched with a KOH aqueous solution or the like to form the high-concentration boron diffusion layer 1.
By using a as an etch stop, the flow path substrate 1 on which the flow paths such as the liquid chamber 6 and the vibration plate 10 are formed is obtained. Then, the nozzle plate 3 (not shown) is bonded onto the flow path substrate 1 with an adhesive to complete the inkjet head.

Next, an ink jet head according to a second embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 52, and an insulating film (silicon oxide film: SiO ₂ film or the like) 64 is formed on the electrode substrate 52 and the insulating film is formed. The film 64 is dug to form the electrode forming recess 62, and the portion other than the electrode forming recess 62 is formed as a joint portion (spacer portion) 63 that is joined to the flow path substrate 1, and the surface of the joint portion 63 is formed. By forming the single crystal or polycrystalline silicon layer 68, the surface of the bonding portion 63 on the bonding surface side is made of silicon.

Then, an electrode 65 is formed on the bottom surface of the electrode forming recess 62 so as to face the vibrating plate 10 with a predetermined gap 66 therebetween, and the vibrating plate 10 and the electrode 65 form an electrostatic force on the vibrating plate 10. Constitutes an electrostatic actuator that is deformed by. Then, a silicon oxide film 67 serving as an electrode protective film is formed on the surface of the electrode 65.

Here, the electrode 65 is, for example, a two-layer structure of a tungsten side film and a polysilicon film, or Ti, T
A refractory metal such as iN or a polycrystalline silicon film doped with impurities can also be used. The flow path substrate 1 and other configurations are the same as in the first embodiment.

With this structure, the bonding surface of the flow path substrate at the junction on the electrode substrate side is a single crystal or polycrystalline silicon layer, and the flow path substrate provided with the vibration plate and the electrode substrate provided with the electrode And are bonded by direct bonding of SiO ₂ —Si. As a result, a protective film is formed on the gap side surface of the diaphragm.
Since (SiO ₂₎ is formed higher drive reliability is obtained, the bonding surface of the channel substrate and the electrode substrate, SiO ₂
Since it is made of -Si, direct bonding is possible at a firing temperature of 800 to 1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

Next, an ink jet head according to a third embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 52, an insulating film (silicon oxide film: SiO ₂ film, etc.) 64 is formed on the electrode substrate 52, and further insulation is performed. By forming a joint portion (spacer portion) 73 made of a single crystal or polycrystalline silicon layer on the film 64, the joint surface side surface of the joint portion 73 is formed of silicon.

Then, an electrode 65 is formed on the surface of the insulating film 64 so as to face the diaphragm 10 with a predetermined gap 70 therebetween, and the diaphragm 10 and the electrode 65 form the diaphragm 10.
An electrostatic actuator that deforms the electric field with an electrostatic force is configured. Then, a silicon oxide film 67 serving as an electrode protective film is formed on the surface of the electrode 65.

Here, the electrode 65 is, for example, a two-layer structure of a tungsten side film and a polysilicon film, or Ti, T
A refractory metal such as iN or a polycrystalline silicon film doped with impurities can also be used. The flow path substrate 1 and other configurations are the same as in the second embodiment.

With this configuration, the bonding surface on the electrode substrate side with the flow channel substrate is a single crystal or polycrystalline silicon layer, and the flow channel substrate provided with the vibrating plate and the electrode substrate provided with the electrode And are bonded by direct bonding of SiO ₂ —Si. As a result, a protective film is formed on the gap side surface of the diaphragm.
Since (SiO ₂₎ is formed higher drive reliability is obtained, the bonding surface of the channel substrate and the electrode substrate, SiO ₂
Since it is made of -Si, direct bonding is possible at a firing temperature of 800 to 1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

In the second and third embodiments, the spacer made of single crystal or polycrystalline silicon is also formed on the same insulating film as the (opposing) electrode is formed on. Therefore, the first embodiment The gap controllability is improved as compared with the above structure.

That is, the gap lengths in the structures of the first and second embodiments are compared as follows. (1st Embodiment) Gap length = concave depth- (under-electrode insulating film thickness + electrode thickness + over-electrode protective film thickness) (second and third embodiments) Gap length = concave depth- (electrode thickness + electrode) Top protective film thickness)

As described above, in the second and third embodiments, the gap length does not depend on the insulating film thickness under the electrode and the depth of the recess can be reduced, so that the gap controllability is improved as compared with the first embodiment. is doing. In particular, as the insulating film thickness between the electrode and the substrate is increased, the gap controllability difference also increases.

Next, the ink jet according to the second embodiment described above.
Please refer to FIG. 10 to FIG. 12 for the manufacturing process of the print head.
And explain. As shown in FIG. 10A, the electrode substrate 5
Prepare a silicon substrate (silicon wafer) 81 to be 2.
Then, the wafer is cleaned by RCA cleaning, and the silicon substrate 8
1 to the insulating film (SiO 2_TwoMembrane) 64 thick
The film thickness is about 0.5 to 2.0 μm. And LP-
Deposition of polycrystalline silicon by CVD etc.
A polycrystalline silicon layer 68 having a thickness of about 0.5 μm is formed.
The surface of the polycrystalline silicon layer 68 is flattened. This flattening
Processing is CMP (Chemical Mechanical Polishing)
The polishing amount is about 0.05 to 0.3 μm. Then bra
Wafer cleaning is performed using CISCLUB and RCA cleaning.
On the surface of the crystalline silicon layer 68, a protective film (SiO 2 _TwoMembrane) 82
A film thickness of about 0.01 to 0.1 μm is formed by CVD or the like.
It

When a single crystal silicon layer is formed instead of the polycrystalline silicon layer 68, an SOI substrate is used, or a single crystal silicon layer is formed by laminating wafers and thinning them by polishing. .

Then, as shown in FIG.
A resist pattern corresponding to the recess 62 by lithography
Wet etch with BHF or CHF_Three+
CF _FourProtective film (SiO 2) by dry etching with gas
_TwoFilm) 82 and etch HNO_ThreeWet at + HF
Toetch or HBr, Cl, CF_Four, SF₆With gas etc.
Etching the polycrystalline silicon layer 68 by dry etching of
In addition, wet etching with BHF or CHF_Three+
CF_FourInsulating film (SiO 2
_TwoThe film 64 is etched to form the recess 62 and the joint 63.
To form. After that, the resist is removed and O_Twoplasma
Perform ashing.

After that, as shown in FIG.
The wafer is cleaned by cleaning or the like, and the electrode material 83 such as TiN, polysilicon, or tungsten silicide is deposited by sputtering, CVD, or the like.

Then, as shown in FIG.
An electrode pattern is formed on the material 83 by photolithography or the like.
Corresponding resist pattern is formed, and Cl-based or F-based
The electrode material 83 is dry-etched with a system gas to form the electrode 65.
Is formed, and after removing the resist O _TwoPerform plasma ashing
U

Then, as shown in FIG. 6B, after the wafer cleaning (RCA cleaning or the like) is performed, the electrode 6 is formed on the insulating film 64.
5 After forming a silicon oxide film (SiO ₂ ) 84 including the surface by a CVD method or the like with a thickness of about 0.05 to 0.3 μm, as shown in FIG. Thus, a pattern 85 for removing the oxide films 84 and 82 on the substrate bonding surface is formed.

Then, as shown in FIG.
Wet etch or CHF_Three+ CF _FourDryer with gas
The oxide film 84 on the substrate bonding surface, etc.
82 is sequentially removed to form an insulating film 67 for protecting the electrode,
After removing resist O_TwoPlasma ashing and electrode 6
The electrode substrate 52 provided with 5, etc. is obtained.

Then, similarly to the manufacturing process of the ink jet head according to the first embodiment described above, a high-concentration boron diffusion layer 1a serving as a vibrating plate is formed and a silicon oxide film 11 is formed on the surface of the flow path substrate. After obtaining the silicon substrate 41 and washing the silicon substrate 41 and the electrode substrate 2 with a mixed aqueous solution of ammonia and hydrogen peroxide as a direct bonding pretreatment, the silicon substrate 41 and the electrode substrate 52 are directly bonded. .

After that, a liquid chamber pattern is formed on the silicon substrate 41 by photolithography or the like, and the silicon substrate 41 is etched with a KOH aqueous solution or the like to form the high-concentration boron diffusion layer 1.
By using a as an etch stop, the flow path substrate 1 on which the flow paths such as the liquid chamber 6 and the vibration plate 10 are formed is obtained. Then, the nozzle plate 3 (not shown) is bonded onto the flow path substrate 1 with an adhesive to complete the inkjet head.

Next, an ink jet head according to the fourth embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 52, an insulating film (silicon oxide film: SiO ₂ film, etc.) 64 is formed on the electrode substrate 52, and further insulation is performed. By forming a joint portion (spacer portion) 73 made of a single crystal or polycrystalline silicon layer on the film 64, the joint surface side surface of the joint portion 73 is formed of silicon.

Then, an electrode 75 made of a single crystal or polysilicon layer is formed on the surface of the insulating film 64 so as to face the vibration plate 10 with a predetermined gap 66 therebetween, and these vibration plate 10 and the electrode 75 are combined. An electrostatic actuator that deforms the diaphragm 10 by electrostatic force is configured. Then, a silicon oxide film 67 serving as an electrode protective film is formed on the surface of the electrode 75. The flow path substrate 1 and other configurations are similar to those of the first and third embodiments.

With this structure, the bonding surface on the electrode substrate side with the flow channel substrate is a single crystal or polycrystalline silicon layer, and the flow channel substrate provided with the vibration plate and the electrode substrate provided with the electrode And are bonded by direct bonding of SiO ₂ —Si. As a result, a protective film is formed on the gap side surface of the diaphragm.
Since (SiO ₂₎ is formed higher drive reliability is obtained, the bonding surface of the channel substrate and the electrode substrate, SiO ₂
Since it is made of -Si, direct bonding is possible at a firing temperature of 800 to 1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

Further, since the joint portion (spacer portion) and the electrode are formed of the same single crystal or polycrystalline silicon (of the same material), the gap controllability is improved as compared with the structures of the second and third embodiments. To do.

That is, the gap lengths in the structures of the second and third embodiments and the fourth embodiment are compared as follows. (Second and Third Embodiments) Gap length = concave depth- (electrode thickness + electrode protective film thickness) (Fourth Embodiment) Gap length = electrode material etching depth-electrode protective film thickness

As described above, in the fourth embodiment, the gap length does not depend on the electrode thickness, and the etching depth of the counter electrode material can be smaller than the recess depths of the second and third embodiments. The gap controllability is improved as compared with the third embodiment. In particular, as the electrode thickness increases, the gap controllability difference also increases.

Next, a manufacturing process of the ink jet head according to the fourth embodiment will be described with reference to FIGS. 14 and 15. As shown in FIG. 15A, the electrode substrate 5
A silicon substrate (silicon wafer) 81 to be 2 is prepared, and wafer cleaning is performed by RCA cleaning or the like, and the silicon substrate 8
1, an insulating film (SiO ₂ film) 64 is formed to a thickness of 0.5 to 2.0 μm by thermal oxidation, CVD or the like.

Then, the polycrystalline silicon is deposited by LP-CVD or the like to form a polycrystalline silicon layer 87 having a thickness of about 0.4 to 1.0 μm. Then, the polycrystalline silicon layer 8
7 is doped with impurities. As impurities, boron,
As the implantation method of phosphorus, arsenic or the like, an ion implantation method and a drive or diffusion method can be used.

Next, the surface of the polycrystalline silicon layer 87 is flattened. This flattening process is performed by CMP (Chemical M
Echanical Polishing) polishing amount 0.05-0.3μm
Do it in a degree. After that, wafer cleaning is performed by brush scrubbing and RCA cleaning, and a protective film (SiO ₂ film) 82 is formed on the surface of the polycrystalline silicon layer 87 by CVD or the like to a thickness of 0.01.
The film is formed to about 0.1 μm.

When a single crystal silicon layer is formed instead of the polycrystalline silicon layer 87, an SOI substrate is used, or a single crystal silicon layer is formed by laminating wafers and thinning them by polishing. .

Then, as shown in FIG.
A resist pattern corresponding to the recess 62 by lithography
Wet etch with BHF or CHF_Three+
CF _FourProtective film (SiO 2) by dry etching with gas
_TwoFilm) 82 and etch HNO_ThreeWet at + HF
Toetch or HBr, Cl, CF_Four, SF₆With gas etc.
Dry etching of the polycrystalline silicon layer 87 to the bottom of the recess.
Etching is performed until the portion becomes the electrode thickness. Then Regis
To remove O_TwoPlasma ashing is performed.

After that, as shown in FIG.
Wafer cleaning such as cleaning is performed to remove the polycrystalline silicon layer 87.
Forming a separation pattern for separating the junction portion 73 and the electrode 75 by wet etching with HNO ₃ + HF or H
The junction 73 and the electrode 75 are formed by further etching the isolation groove 88 in the polycrystalline silicon layer 87 by dry etching with Br, Cl, CF ₄ , SF ₆ gas or the like. Then, the resist is removed and O ₂ plasma ashing is performed.

Then, as shown in FIG. 15A, after the wafer cleaning (RCA cleaning or the like) is performed, the silicon oxide film (S
iO ₂₎ 84 was deposited in a thickness of about 0.05 to 0.3 m CVD method or the like, as shown in FIG. (b), the oxide film 84 of the bonding surface substrate leaving an electrode protective portion photolithography , 82 is formed to form a pattern 85.

Then, as shown in FIG.
By wet etching or dry etching with CHF ₃ + CF ₄ gas to form the oxide film 8 on the substrate bonding surface or the like.
4, 82 are sequentially removed to form an insulating film 67 for protecting the electrode, and after removing the resist, O ₂ plasma ashing is performed to obtain the electrode substrate 52 provided with the electrodes 75 and the like.

Then, similarly to the manufacturing process of the ink jet head according to the first embodiment described above, a high-concentration boron diffusion layer 1a serving as a vibrating plate is formed and a silicon oxide film 11 is formed on the surface of the flow path substrate. After obtaining the silicon substrate 41 and washing the silicon substrate 41 and the electrode substrate 2 with a mixed aqueous solution of ammonia and hydrogen peroxide as a direct bonding pretreatment, the silicon substrate 41 and the electrode substrate 52 are directly bonded. .

After that, a liquid chamber pattern is formed on the silicon substrate 41 by photolithography or the like, and the silicon substrate 41 is etched with a KOH aqueous solution or the like to form the high-concentration boron diffusion layer 1.
By using a as an etch stop, the flow path substrate 1 on which the flow paths such as the liquid chamber 6 and the vibration plate 10 are formed is obtained. Then, the nozzle plate 3 (not shown) is bonded onto the flow path substrate 1 with an adhesive to complete the inkjet head.

Next, an ink jet head according to the fifth embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 52, an insulating film (silicon oxide film: SiO ₂ film, etc.) 64 is formed on the electrode substrate 52, and further insulation is performed. A single crystal or polycrystal silicon layer 93 is formed on the film 64, and the polycrystal silicon layer 87 is dug to form the bonding portion (spacer portion) 7
By forming 3 and the electrode 75, the surface of the joint portion 73 on the joint surface side is formed of silicon.

In this head, the polycrystalline silicon layer 87 also serves as an electrode 75 facing the vibrating plate 10 with a predetermined gap 66 therebetween.
5 and 5 constitute an electrostatic actuator that deforms the diaphragm 10 by electrostatic force. Then, a silicon oxide film 67 serving as an electrode protective film is formed on the surface of the electrode 75. The flow path substrate 1 and other configurations are similar to those of the first and third embodiments.

With this configuration, the bonding surface on the electrode substrate side with the flow channel substrate is a single crystal or polycrystalline silicon layer, and the flow channel substrate provided with the vibration plate and the electrode substrate provided with the electrode And are bonded by direct bonding of SiO ₂ —Si. As a result, a protective film is formed on the gap side surface of the diaphragm.
Since (SiO ₂₎ is formed higher drive reliability is obtained, the bonding surface of the channel substrate and the electrode substrate, SiO ₂
Since it is made of -Si, direct bonding is possible at a firing temperature of 800 to 1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

Moreover, since the gap between the diaphragm and the electrode is formed by digging the polycrystalline silicon layer (or the single crystal silicon layer may be used) which becomes the electrode, a special sealing step is performed. The gap can be sealed without.

Next, the manufacturing process of the ink jet head according to the fifth embodiment will be described with reference to FIGS. 17 and 18. As shown in FIG. 17A, the electrode substrate 5
A silicon substrate (silicon wafer) 81 to be 2 is prepared, and wafer cleaning is performed by RCA cleaning or the like, and the silicon substrate 8
1, an insulating film (SiO ₂ film) 64 is formed to a thickness of 0.5 to 2.0 μm by thermal oxidation, CVD or the like.

Then, the polycrystalline silicon is deposited by LP-CVD or the like to form a polycrystalline silicon layer 87 having a thickness of about 0.4 to 1.0 μm. Then, the polycrystalline silicon layer 8
7 is doped with impurities. As impurities, boron,
As the implantation method of phosphorus, arsenic or the like, an ion implantation method and a drive or diffusion method can be used.

Then, the surface of the polycrystalline silicon layer 87 is flattened. This flattening process is performed by CMP (Chemical M
Echanical Polishing) polishing amount 0.05-0.3μm
Do it in a degree. After that, wafer cleaning is performed by brush scrubbing and RCA cleaning, and a protective film (SiO ₂ film) 82 is formed on the surface of the polycrystalline silicon layer 87 by CVD or the like to a thickness of 0.01.
The film is formed to about 0.1 μm.

When a single crystal silicon layer is formed instead of the polycrystalline silicon layer 87, an SOI substrate is used, or a single crystal silicon layer is formed by laminating a wafer and thinning it by polishing. .

Then, as shown in FIG.
A resist pattern corresponding to the recess 62 by lithography
Wet etch with BHF or CHF_Three+
CF _FourProtective film (SiO 2) by dry etching with gas
_TwoFilm) 82 and etch HNO_ThreeWet at + HF
Toetch or HBr, Cl, CF_Four, SF₆With gas etc.
Dry etching of the polycrystalline silicon layer 87 to the bottom of the recess.
Etching is performed until the portion becomes the electrode thickness. Then Regis
To remove O_TwoPlasma ashing is performed.

After that, as shown in FIG.
Wafer cleaning such as cleaning is performed to remove the polycrystalline silicon layer 87.
Forming a separation pattern for separating the junction 73 of each channel and the electrode 75, and further performing a wet etching with HNO ₃ + HF or a dry etching with HBr, Cl, CF ₄ , SF ₆ gas or the like to further form a polycrystalline silicon layer. By forming the separation groove 89 in 87, the junction 73 of each channel and the electrode 75 are formed. Then, the resist is removed and O ₂ plasma ashing is performed.

Then, as shown in FIG. 18A, after the wafer cleaning (RCA cleaning or the like) is performed, the silicon oxide film (S
iO ₂₎ 84 was deposited in a thickness of about 0.05 to 0.3 m CVD method or the like, a pattern 85 for removing the oxide film 84, 82 of the bonding surface substrate leaving an electrode protective portion photolithography Form.

Then, as shown in FIG. 9B, wet etching with HF or dry etching with CHF ₃ + CF ₄ gas is performed to form an oxide film 8 on the substrate bonding surface or the like.
4, 82 are sequentially removed to form an insulating film 67 for protecting the electrode, and after removing the resist, O ₂ plasma ashing is performed to obtain the electrode substrate 52 provided with the electrodes 75 and the like.

Then, similarly to the manufacturing process of the ink jet head according to the first embodiment described above, a high-concentration boron diffusion layer 1a serving as a vibrating plate is formed and a silicon oxide film 11 is formed on the surface of the flow path substrate. After obtaining the silicon substrate 41 and washing the silicon substrate 41 and the electrode substrate 2 with a mixed aqueous solution of ammonia and hydrogen peroxide as a direct bonding pretreatment, the silicon substrate 41 and the electrode substrate 52 are directly bonded. .

After that, a liquid chamber pattern is formed on the silicon substrate 41 by photolithography or the like, and the silicon substrate 41 is etched with a KOH aqueous solution or the like to form the high-concentration boron diffusion layer 1.
By using a as an etch stop, the flow path substrate 1 on which the flow paths such as the liquid chamber 6 and the vibration plate 10 are formed is obtained. Then, the nozzle plate 3 (not shown) is bonded onto the flow path substrate 1 with an adhesive to complete the inkjet head.

Next, an ink jet head according to the sixth embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 112, and an insulating film (silicon oxide film: SiO ₂ film or the like) 114 is formed on the electrode substrate 112 and the insulation is performed. An electrode 115 made of single crystal silicon or polysilicon is provided on the film 114 so as to face the diaphragm 10 with a predetermined gap 116 therebetween.
5 and 5 constitute an electrostatic actuator that deforms the diaphragm 10 by electrostatic force.

Then, a silicon oxide film 119 is formed on the insulating film 114 and the electrode 115 as an insulating film for forming a spacer portion (joint portion) and an electrode protective film, and the silicon oxide film 119 is dug. To form a concave portion 112, and to make the portion other than the concave portion 112 a joint portion (spacer portion) 11
3, and a single crystal silicon or polycrystalline silicon layer 118 is formed on the surface of the joint portion 113 on the joint surface side.
The surface on the side of the bonding surface of 3 is made of silicon. At this time, the bottom portion of the recess 112 of the silicon oxide film 119 becomes the electrode protection film 117. The structure of the flow path substrate 1 is the same as that of the first embodiment.

Next, an ink jet head according to the seventh embodiment of the present invention will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm. In this inkjet head, a single crystal silicon substrate or a polycrystalline silicon substrate is used as the electrode substrate 102, an insulating film (silicon oxide film: SiO ₂ film, etc.) 114 is formed on the electrode substrate 102, and the insulation is performed. An electrode 115 made of single crystal silicon or polysilicon is provided on the film 114 so as to face the diaphragm 10 with a predetermined gap 116 therebetween.
5 and 5 constitute an electrostatic actuator that deforms the diaphragm 10 by electrostatic force.

Then, a silicon oxide film 119 as an insulating film for forming the electrode protective film 117 is formed on the insulating film 114 and the electrode 115, and the silicon oxide film 119 is formed.
By forming a single crystal silicon or polycrystalline silicon layer on the above and digging the recessed portion 122, a joint portion (spacer portion) 123 made of the single crystal silicon or polycrystalline silicon layer is formed, and the joint surface side of the joint portion 123 is formed. The surface is made of silicon. The structure of the flow path substrate 1 is the same as that of the first embodiment.

Since the sixth and seventh embodiments are configured as described above, the bonding surface on the electrode substrate side with the flow path substrate is a single crystal or polycrystalline silicon layer, and the vibration plate is provided. The flow channel substrate and the electrode substrate provided with electrodes are made of Si.
It is bonded by direct bonding of O ₂ —Si. This allows
Since the protective film (SiO ₂ ) is formed on the gap side surface of the vibration plate, high driving reliability is obtained, and the bonding surface of the flow path substrate and the electrode substrate is SiO ₂ —Si. Direct bonding is possible at a firing temperature of ˜1100 ° C. Furthermore, it is not necessary to perform highly accurate alignment when the flow path substrate and the electrode substrate are attached. And, by using cheap and stable silicon for the substrate, it becomes possible to manufacture using a widely used semiconductor process, and it becomes possible to manufacture at low cost.

A spacer (junction) made of single crystal or polycrystalline silicon is formed on the insulating film on the (opposing) electrode, and a part of the silicon layer (and also the insulating film layer) is dug to form a gap. Since the gap is formed, the gap controllability is further improved as compared with the fifth embodiment, and an inkjet head with less characteristic variation can be obtained. Also,
Since a material other than silicon can be used as the counter electrode material, the width of the process can be widened. For example, by using TiN or WSi, it is possible to reduce the resistance and to easily take out the pad. Of course, other materials can be selected.

Next, the manufacturing process of the ink jet head according to the sixth embodiment will be described with reference to FIG. As shown in FIG. 3A, a silicon substrate (silicon wafer) 131 to be the electrode substrate 102 is prepared, and RC
A wafer is cleaned by A cleaning or the like, and an insulating film (SiO ₂ film) 114 is formed on the silicon substrate 131 by thermal oxidation, CVD or the like to a thickness of about 0.5 to 2.0 μm.

Then, an electrode material 132 such as TiN, polysilicon or WSi is formed on the insulating film 114 by a method such as CVD or sputtering. Next, as shown in FIG. 3B, an electrode pattern is formed, the electrode material 132 is dry-etched with a Cl-based or F-based gas to form an electrode 115, the resist is removed, and O ₂ plasma ashing is performed. I do.

Thereafter, as shown in FIG. 6C, wafer cleaning (RCA cleaning or the like) is performed, and then a silicon oxide film (Si
O ₂ ) 119 is deposited to a thickness of about 0.05 to 0.5 μm by a CVD method or the like, and then wafer cleaning is performed by RCA cleaning or the like, and L
Polycrystalline silicon is deposited by P-CVD or the like to a thickness of 0.
A polycrystalline silicon layer 118 having a thickness of about 1 to 0.5 μm is formed. Then, the polycrystalline silicon layer 118 is doped with impurities. As impurities, boron, phosphorus, arsenic, or the like can be used. As an implantation method, an ion implantation method, a drive method, a diffusion method, or the like can be used.

Then, the surface of the polycrystalline silicon layer 118 is flattened. This flattening process is performed by CMP (Chemical
Mechanical polishing) polishing amount 0.05-0.3μ
Do about m. Then, the wafer is cleaned by brush scrubbing and RCA cleaning.

When a single crystal silicon layer is formed instead of the polycrystalline silicon layer 118, an SOI substrate is used, or a single crystal silicon layer is formed by laminating wafers and thinning them by polishing. .

Next, as shown in FIG. 7D, a resist pattern corresponding to the recess 112 is formed by photolithography, and the polycrystalline silicon layer 118 is dry-etched with HBr, Cl, CF ₄ , SF ₆ gas or the like. To etch. After that, wet etching with HF or CHF
Dry etching with ₃ + CF ₄ gas is performed to etch the silicon oxide film 119 to form an insulating film 1 for electrode protection.
After forming 17 and removing the resist, O ₂ plasma ashing is performed to obtain the electrode substrate 102 provided with the electrodes 115 and the like.

Then, similarly to the manufacturing process of the ink jet head according to the first embodiment described above, a high-concentration boron diffusion layer 1a serving as a vibrating plate is formed, and a silicon oxide film 11 is formed on the surface of the flow path substrate. After obtaining the silicon substrate 41 and washing the silicon substrate 41 and the electrode substrate 2 with a mixed aqueous solution of ammonia and hydrogen peroxide as a direct pre-bonding treatment, the silicon substrate 41 and the electrode substrate 102 are directly bonded. .

Thereafter, a liquid chamber pattern is formed on the silicon substrate 41 by photolithography or the like, and the silicon substrate 41 is etched with a KOH aqueous solution or the like to form the high concentration boron diffusion layer 1
By using a as an etch stop, the flow path substrate 1 on which the flow paths such as the liquid chamber 6 and the vibration plate 10 are formed is obtained. Then, the nozzle plate 3 (not shown) is bonded onto the flow path substrate 1 with an adhesive to complete the inkjet head.

In the present invention, an electrostatic microactuator having a vibrating plate as a movable plate, such as a micropump,
The same can be applied to a micro switch (micro relay), a multi-optical lens actuator (micro mirror), a micro flow meter, a pressure sensor, and the like.
Furthermore, for example, as a droplet discharge head other than the inkjet head, for example, a liquid resist for patterning,
It can also be applied to a droplet discharge head that discharges a DNA sample.

Further, in the above embodiment, the present invention is applied to the side shooter type ink jet head in which the displacement direction of the diaphragm and the ink droplet ejection direction are the same.
The same can be applied to an inkjet head of an edge shooter system in which the displacement direction of the diaphragm and the ejection direction of ink droplets are orthogonal to each other.

[0107]

As described above, according to the droplet discharge head according to the present invention, the second substrate is provided with the silicon oxide film on the surface of the first substrate provided with the vibration plate on the second substrate side.
A bonding portion for bonding to the first substrate is provided on the substrate side, and at least the bonding surface side surface of the bonding portion is formed of silicon,
Since the substrate and the second substrate are bonded by the direct bonding of the silicon oxide film and the silicon of the bonding portion, high driving reliability can be obtained, and the first substrate and the electrode can be accurately aligned. Instead, it is possible to directly bond the silicon oxide films at a low temperature as compared with the bonding of the silicon oxide films, and it is possible to manufacture the head at low cost.

Here, the second substrate is formed of a single crystal silicon substrate, and the single crystal silicon substrate is dug to form a bonding portion in which at least the bonding surface side surface is made of silicon, so that the cost is reduced. be able to.

Further, the gap controllability is improved and the characteristics are improved by disposing the electrodes on the insulating film provided on the second substrate and providing the bonding portion at least the bonding surface side surface of which is made of silicon on the insulating film. Variation can be reduced. In this case, the manufacturing process can be shortened and the cost can be further reduced by forming the electrode from single crystal or polycrystalline silicon.
Further, by forming the bonding portion of the second substrate from the member forming the electrode, the gap controllability is improved and the variation in the characteristics can be reduced. Furthermore, by forming the bonding portion of the second substrate from single crystal or polycrystalline silicon provided in the insulating film that protects the electrodes, the gap controllability is further improved, the variation in characteristics can be reduced, and the electrode material A wider range of choices.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating an inkjet head according to a first embodiment of the present invention.

FIG. 2 is an explanatory top view of the same head without a nozzle plate.

FIG. 3 is an explanatory sectional view of the same head taken along the longitudinal direction of the diaphragm.

FIG. 4 is an enlarged cross-sectional explanatory view of a main part of the head along a lateral direction of a diaphragm.

FIG. 5 is a cross-sectional explanatory diagram illustrating a manufacturing process of the head according to the first embodiment.

FIG. 6 is an explanatory cross-sectional view illustrating a step following the step of FIG.

FIG. 7 is a cross-sectional explanatory diagram illustrating a step that follows FIG.

FIG. 8 is an enlarged cross-sectional explanatory view of a main part along a lateral direction of a diaphragm of an inkjet head according to a second embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional explanatory view of a main part along a lateral direction of a diaphragm of an inkjet head according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional explanatory diagram illustrating a manufacturing process of the head according to the second embodiment.

11 is a cross-sectional explanatory diagram illustrating a step following the step of FIG.

FIG. 12 is a cross-sectional explanatory diagram illustrating a step following FIG.

FIG. 13 is an enlarged cross-sectional explanatory view of a main part along a lateral direction of a diaphragm of an inkjet head according to a fourth embodiment of the present invention.

FIG. 14 is a cross-sectional explanatory diagram illustrating a manufacturing process of the head according to the fourth embodiment.

FIG. 15 is a sectional explanatory diagram illustrating a step following the step of FIG.

FIG. 16 is an enlarged cross-sectional explanatory view of a main part along a lateral direction of a diaphragm of an inkjet head according to a fifth embodiment of the present invention.

FIG. 17 is a cross-sectional explanatory view explaining a manufacturing process of the head according to the sixth embodiment.

FIG. 18 is a cross-sectional explanatory diagram illustrating a step following the step of FIG. 17;

FIG. 19 is an enlarged cross-sectional explanatory view of a main part along the lateral direction of the diaphragm of the inkjet head according to the sixth embodiment of the present invention.

FIG. 20 is an enlarged cross-sectional explanatory view of essential parts along a lateral direction of a diaphragm of an inkjet head according to a seventh embodiment of the present invention.

FIG. 21 is a cross-sectional explanatory view explaining a manufacturing process of the head according to the sixth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flow path substrate (1st substrate), 2, 52, 102 ... Electrode substrate (2nd substrate), 3 ... Nozzle plate, 4 ... Nozzle, 6 ... Liquid chamber, 7 ... Fluid resistance part, 8 ... Common liquid chamber 10 ... diaphragm, 1
3, 63, 73, 113, 123 ... Joints, 15, 6
5, 75, 115 ... Electrodes, 16, 66, 116 ... Gap, 68, 118 ... Polycrystalline silicon film.

Claims (6)

[Claims] 1. An electrode facing a vibrating plate forming a wall surface of a part of a liquid chamber communicating with a nozzle for discharging a droplet,
In a droplet discharge head that deforms the vibrating plate by electrostatic force to eject ink droplets from the nozzles, a silicon oxide film is formed on the second substrate side surface of the first substrate provided with the vibrating plate, and the electrode is A bonding portion for bonding to the first substrate is provided on the side of the second substrate to be provided, and at least the surface of the bonding surface side of the bonding portion is made of silicon, and the first substrate and the second substrate are formed of the silicon oxide film. A droplet discharge head, characterized in that it is joined by direct joining with the silicon of the joining portion. 2. The droplet discharge head according to claim 1, wherein the second substrate is formed of a single crystal silicon substrate,
A droplet discharge head, wherein at least the bonding surface side surface is made of silicon to form the bonding portion by digging the single crystal silicon substrate. 3. The droplet discharge head according to claim 1, wherein the electrode is arranged on an insulating film provided on the second substrate, and at least the surface on the bonding surface side is made of silicon on the insulating film. A droplet discharge head having a joint portion. 4. The droplet discharge head according to claim 2, wherein the electrode is formed of single crystal or polycrystalline silicon. 5. The droplet discharge head according to claim 1, wherein the bonding portion of the second substrate is formed of a member forming the electrode. 6. The droplet discharge head according to claim 1, wherein the bonding portion of the second substrate is formed of single crystal or polycrystalline silicon provided on an insulating film that protects the electrode. And a droplet discharge head.