JP2003011365A - Ink jet head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a crack of a substrate is developed. SOLUTION: After a first silicon substrate 31 and a second silicon substrate 32 are bonded, a through hole 19 for supplying ink is made in the second silicon substrate 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head and a method for manufacturing the same.

[0002]

2. Description of the Related Art 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 is provided with a nozzle for ejecting ink droplets and an ejection chamber (ink flow) communicating with the nozzle. Channel, ink chamber, pressure chamber, liquid chamber, pressurizing chamber, pressurizing liquid chamber, etc.) and pressure generating means for pressurizing ink in the discharge chamber. Ink droplets are ejected from the nozzle by changing the pressure / volume.

For example, in Japanese Unexamined Patent Publication No. HEI 6-71882, a silicon substrate is etched to face a diaphragm so as to sandwich a discharge chamber and a discharge chamber substrate having a diaphragm forming a wall surface of the discharge chamber. There is disclosed an electrostatic ink jet head in which an electrode substrate on which electrodes for forming are arranged and a nozzle substrate on which nozzles are formed are joined.

Further, as a method of providing a supply port for supplying ink to the ink jet head from the outside, there is a conventional method disclosed in Japanese Patent Laid-Open No. 62-152862. In this method, a hole for connecting an ink supply pipe is opened in the head chip to form a concave shape so that ink can be supplied. In this manufacturing method, ink is supplied to each inkjet head. There is an inconvenience that it is not suitable for mass production because it requires drilling for the intake port.

On the other hand, when a plurality of ink jet heads are made from a wafer-like substrate which has been preliminarily punched and then a large number of ink jet heads are made at one time by cutting the ink jet head, the wafer-like substrate is finely etched. It is necessary to form a different electrode.

However, if a fine electrode is to be formed on a substrate having holes, a photosensitive photoresist is applied thinly and uniformly by a spin coating method for fine patterning for etching. Becomes impossible, and there arises a disadvantage that it is not possible to form electrodes with high precision and high density. Especially in the electrostatic ink jet head,
Although photoresist coating by spin coating is indispensable for producing a shallow groove of about 0.2 μm and a wiring pattern of 5 to 10 μm pitch, it is necessary to perform drilling in advance before the cutting process. It was

Therefore, as a conventional method of manufacturing an ink jet head, as described in JP-A-11-123824, a nozzle for ejecting an ink droplet, an ejection chamber communicating with this nozzle, and this ejection chamber are provided. In an inkjet head manufacturing method including an ink intake port for supplying ink, an electromechanical conversion element provided in a part of the ejection chamber, and an electrode provided corresponding to the electromechanical conversion element, an insulating property is provided. Forming a pattern of electrodes on the first substrate of the first substrate, and then forming a through hole for forming an ink intake port on the first substrate on which the electrode pattern has been formed. There is one that joins the second substrate on which is formed. In this case, in the drilling process, drilling is performed by drilling, melting by laser light or sublimation, or ultrasonic processing.

[0008]

In the conventional method of manufacturing an ink jet head described above, since the electrode pattern is formed before the hole forming process, the photoresist coating and patterning can be performed with high accuracy. Drill,
Since the process is performed by laser or ultrasonic waves, in an inkjet head that can form only small holes and has a large number of nozzles, insufficient ink supply causes problems such as ejection failure.

Therefore, when a large ink intake port is formed by forming a large number of ink intake ports or by forming them densely and communicating with each other, the strength of the substrate on which the electrodes are formed becomes small, and the subsequent bonding causes damage and yield. The problem arises that Further, when a large number of ink intake ports are formed, there is a problem in that the cost increases as the number increases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet head capable of improving the yield and reducing the cost, and a manufacturing method thereof.

[0011]

In order to solve the above-mentioned problems, an ink jet head according to a first aspect of the present invention is configured such that an ink is applied to a second silicon substrate after the second silicon substrate and the first silicon substrate are bonded to each other. The configuration is such that a through hole for supply is formed. According to a second aspect of the present invention, there is provided the inkjet head according to the first aspect, wherein the through-hole for supplying ink is formed by anisotropic etching.

An ink jet head according to a third aspect is
The first silicon substrate has a recess serving as a common liquid chamber, and the second
The silicon substrate has a through hole for supplying ink, which communicates with the common liquid chamber, and the width of the through hole is smaller than the width of the common liquid chamber.

An ink jet head according to a fourth aspect is
The second silicon substrate has a through-hole for supplying ink, and the through-hole is divided into a plurality of parts.

An ink jet head according to a fifth aspect is
The second silicon substrate has a through hole for ink supply, and the first silicon substrate has a recess communicating with the through hole for ink supply and the ejection chamber. The recess is divided into a plurality of parts. It is configured to be.

An ink jet head according to a sixth aspect is
The inkjet head according to any one of claims 1 to 5, wherein the second silicon substrate has a (110) plane orientation.
The through holes are formed so as to be aligned with the <110> or <112> direction of the silicon substrate.

An ink jet head according to a seventh aspect is
The inkjet head according to any one of claims 1 to 5, wherein the second silicon substrate has a (100) plane orientation.
The through holes are formed so as to coincide with the <011> direction of the silicon substrate.

An ink jet head according to claim 8 is
Through holes for ink supply are formed by anisotropic etching in the second silicon substrate having the (100) plane orientation, and <110 of the first silicon substrate having the (100) plane orientation is formed.
The <> direction of the second silicon substrate and the <110> direction are parallel to each other.

An ink jet head according to a ninth aspect is
Through holes for ink supply are formed by anisotropic etching in the second silicon substrate having the (100) plane orientation, and <1-1 of the first silicon substrate having the (110) plane orientation is formed.
The 2> direction and the <110> direction of the second silicon substrate are parallel to each other.

In an ink jet head according to a tenth aspect of the present invention, the first silicon substrate is an SOI substrate obtained by bonding a base wafer having a (100) plane orientation and a bond wafer having a (100) plane orientation, and the second silicon substrate is (10
It consists of a silicon substrate having a (0) plane orientation, and has a <110> direction of a base wafer and a <1> of a bond wafer having a (100) plane orientation.
The 10> direction and the <110> direction of the second silicon substrate are parallel to each other.

In the ink jet head according to the eleventh aspect, the first silicon substrate is an SOI substrate obtained by bonding a base wafer having a (110) plane orientation and a bond wafer having a (100) plane orientation, and the second silicon substrate is (10
A silicon substrate having a (0) plane orientation, wherein the <1-12> direction of the base wafer, the <110> direction of the bond wafer, and the <110> direction of the second silicon substrate having a (110) plane orientation are parallel to each other. It was done.

In an ink jet head according to a twelfth aspect, a through hole for supplying ink is formed in the second silicon substrate by anisotropic etching, and a portion corresponding to the through hole of the first silicon substrate is second. The structure is such that an opening is formed by anisotropically etching from the bonding surface side with the silicon substrate.

An ink jet head manufacturing method according to a thirteenth aspect is a method for manufacturing the ink jet head according to the twelfth aspect, wherein the portion corresponding to the through hole of the first silicon substrate is made of a high-concentration boron layer. In the step of anisotropically etching the first silicon substrate from the bonding surface side with the second silicon substrate, an etching solution having a high etching rate for the high-concentration boron layer is used first, and then an etching rate for the high-concentration boron layer is increased. The configuration is such that the etching is sequentially performed with a small etching solution.

According to a fourteenth aspect of the present invention, an ink jet head is constructed such that the surfaces of the second silicon substrate and the first silicon substrate are all polished surfaces.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of the present invention will be described with reference to FIGS. Note that FIG.
2 is an exploded perspective view of the inkjet head according to the same embodiment, FIG. 2 is a plan view of the head without a nozzle plate, FIG. 3 is a schematic cross-sectional view of the head along a longitudinal direction of a discharge chamber, and FIG. FIG. 3 is a schematic cross-sectional explanatory view taken along the lateral direction of the ejection chamber of the head.

This ink jet head has a flow channel substrate 1 which is a first silicon substrate, an electrode substrate 2 which is a second silicon substrate provided below the flow channel substrate 1, and a flow channel substrate 1.
It is composed of a laminated structure formed by laminating a nozzle plate 3 which is a third substrate provided on the upper side of the ejection chamber 6 and an ejection chamber 6 which is an ink flow path through which a plurality of nozzles 4 communicate with each other, and a fluid resistance portion 7 in the ejection chamber 6. The common liquid chamber 8 and the like communicating with each other are formed.

The flow path substrate 1 is formed of a single crystal silicon substrate having a (110) plane orientation, and forms a discharge chamber 6 and a diaphragm 10 that forms a diaphragm 10 forming a wall surface serving as the bottom of the discharge chamber 6 (the space between the recesses is the discharge space). It forms a partition wall of the chamber 6), and a recess forming the common liquid chamber 8 is formed. Electrode substrate 2 of this flow path substrate 1
In order to prevent dielectric breakdown or short circuit between the diaphragm 10 and an electrode 15 which will be described later during driving, an insulating film 11 such as SiO ₂ having a thickness of 0.1 μm is formed by thermal oxidation.

The electrode substrate 2 is formed of a single crystal silicon substrate having a (110) plane orientation, a thermal oxide film layer 2a is formed on this silicon substrate by a thermal oxidation method, and a groove portion for electrode formation is formed on the thermal oxide film layer 2a. The (recess) 14 is formed, and the electrode 15 is formed on the bottom surface of the recess 14 so as to face the vibrating plate 10 with a predetermined gap 16, and the vibrating plate 15 is displaced by the electrode 15 and the vibrating plate 10. An actuator section (pressure generating means) that changes the internal volume of the discharge chamber 6 is configured. That is, the electrode 15 which is a part of the pressure generating means is formed on the electrode substrate 2.

The vibrating plate 1 is placed on the electrode 15 of the electrode substrate 2.
In order to prevent the electrode 15 from being damaged by contact with 0, an insulating layer 17 of SiO ₂ is formed. An electrode pad portion 15a for extending the electrode 15 to the vicinity of the end portion of the electrode substrate 2 and connecting it to an external drive circuit via a connecting means.
Is formed.

Here, the electrode substrate 2 has a thickness of 0.6 mm.
A thermal oxide film 2a having a thickness of 2 μm is formed on the surface of the single crystal silicon substrate of, and a concave portion 14 is formed on the thermal oxide film 2a by etching with an HF solution.
4, an electrode material having high heat resistance such as titanium nitride is formed into a desired thickness by a film forming technique such as sputtering, CVD, vapor deposition, and then a photoresist is formed and etched to form a recess 14 in the recess 14. Only the electrode 15 is formed.

Further, the electrode substrate 2 which is the second silicon substrate has a through hole 19 which becomes an ink intake port 18 for supplying ink to the common liquid chamber 8 of the flow path substrate 1 which is the first silicon substrate. It is provided. This ink intake 18
The through hole 19 is formed after the flow path substrate 1 and the electrode substrate 2 are bonded together, and is formed in a rectangular shape parallel to the alignment of the discharge chamber 6. As a result, the through hole 19 serving as the ink intake port 18 can be formed in a state where the strength of the substrate is secured, and damage during manufacture is prevented.

Here, the width of the through-hole 19 serving as the ink intake port 18 is formed smaller than the width of the common liquid chamber 8. That is, when the common liquid chamber 8 is formed by the flow path substrate 1 which is the first silicon substrate having the crystal plane orientation (110), as shown in FIG.
As shown in FIG. 5, the partition wall of the common liquid chamber 8 has a sawtooth shape. At this time, if the width of the through-hole 19 serving as the ink intake port 18 on the flow path substrate 1 side is larger than the width of the common liquid chamber 8. Since the saw teeth are present in the ink flow from the ink intake port 18, the ink may not flow efficiently and the ink supply may be insufficient. Therefore, by making the width of the through-hole 19 serving as the ink intake port 18 on the flow path substrate 1 side smaller than the width of the common liquid chamber 8, it is possible to ensure an efficient flow of ink.

After the flow path substrate 1 and the electrode substrate 2 described above are bonded by a process such as anodic bonding or direct bonding, the gap 1 is formed.
The opening 6 is hermetically sealed from the outside air with a sealing material 20 such as an epoxy resin. The length of the gap 16 (distance between the vibration plate 10 and the electrode 15) after joining the flow path substrate 1 and the electrode substrate 2 is 0.2 μm.

The nozzle plate 3 is made of, for example, glass or plastic, a metal such as stainless steel, or a thin plate such as silicon, and the nozzles 4 corresponding to the number of the discharge chambers 6 are formed at positions corresponding to the discharge chambers 6. Further, the fluid resistance portion 7 is formed so that the discharge chamber 6 of the flow path substrate 1 and the common liquid chamber 8 communicate with each other.

A common electrode 12 is provided on the flow path substrate 1. The common electrode 12 is attached by sputtering a metal such as Al and sintering (thermally diffusing) it to ensure electrical continuity with the flow path substrate 1 and the ohmic contact with the flow path substrate 1 made of a semiconductor substrate. Making contact.
Then, for example, a lead wire is bonded to the electrode pad portion 15a communicating with the common electrode 12 and each individual electrode 15 to connect the driver 21.

Further, an ink supply pipe is adhered and connected to the ink intake port 18, so that the common liquid chamber 8, the discharge chamber 6 and the like are supplied from an ink tank (not shown) through the ink intake port 18. Fill with ink. As the ink to be used, one prepared by dissolving or dispersing a surfactant such as ethylene glycol and a dye or a pigment in a main solvent such as water, alcohol or toluene is used. Hot melt ink can also be used if a heater is attached.

In the thus constructed ink jet head, the surface of the electrode 15 is charged to a positive potential by applying a positive voltage pulse to the individual electrode 15 by the driver 21, for example. Since the lower surface of the vibrating plate 10 facing the electrode 15 is charged to a negative potential, the vibrating plate 10 is attracted by the electrostatic force and bends in the direction in which the distance between the vibrating plate 10 and the individual electrodes 15 is narrowed. At this time, the vibration plate 10 bends, so that ink is supplied from the reservoir (common liquid chamber) 8 to the ejection chamber 6 via the orifice (fluid resistance portion) 7.

Therefore, by turning off the voltage pulse applied to the individual electrode 15 and discharging the accumulated charge, the deflected diaphragm 10 is restored to its original position as described above, Due to the restoration operation, the internal pressure of the ejection chamber 6 rapidly rises, and the ink droplets are ejected from the nozzle 4 toward the recording paper (not shown).

Next, the manufacturing process of this ink jet head will be described with reference to FIGS. First, FIG.
As shown in (a), a high-concentration boron diffusion layer 31a is formed by diffusing boron by a coating diffusion method using a first silicon substrate 31 having a (110) plane orientation and a thickness of 500 μm to be the flow path substrate 1. To form.

Specifically, the silicon substrate 31 and the solid diffusion source are arranged facing each other and set in a furnace at 750 ° C. Nitrogen containing 0.25% oxygen is flowed in the furnace. The temperature of the furnace was raised to 1125 ° C. at a rate of 8 ° C./minute, held in that state for 50 minutes, then lowered to 750 ° C. at a rate of 8 ° C./minute, and a sample was taken out to form a high-concentration boron diffusion layer 31a. It

After that, B formed on the surface of the silicon substrate
_{The 2} O ₃ layer is removed with hydrofluoric acid. A compound layer of silicon and boron is formed under the B ₂ O ₃ layer, and when it is removed, it can be removed by hydrofluoric acid by oxidizing it. However, even if the compound layer is oxidized and the compound layer is removed by hydrofluoric acid in this way, the silicon surface in which boron is diffused is roughened, so that it cannot be bonded by direct bonding performed later.

Therefore, the surface property (Ra = 5 nm or less) capable of being directly bonded by removing the entire compound layer by CMP polishing was obtained. In CMP polishing, the outermost surface can be uniformly polished in-plane at 1000 Å or less. Therefore, the change in the high-concentration boron diffusion layer 31a is small, and the diffusion condition may be determined in consideration of the polishing amount. Alternatively, CMP polishing may be performed after the compound layer is removed by oxidation and hydrofluoric acid treatment.

On the other hand, in a separate step, a thermal oxide film 2a is formed on the second silicon substrate 32 having a thickness of 600 μm and having a (100) plane orientation, which will be the electrode substrate 2, and the thermal oxide film 2a is etched. Thus, the concave portion 14 is formed, and the individual electrode 15, the insulating layer 17 and the like are formed in the concave portion 14.

Then, these first silicon substrate 31
Are directly bonded onto the second silicon substrate 32. Here, 900 is obtained by pre-bonding under reduced pressure.
Bonding was performed by heat treatment at 2 ° C. for 2 hours.

Then, as shown in FIG. 6B, the first silicon substrate 31 is thinned by polishing to a thickness of 100 μm. Subsequently, as shown in FIG. 3C, silicon nitride films 34a and 34b are formed on the outer surfaces of the bonded silicon substrates 31 and 32 by LP-CVD.

Then, as shown in FIG. 3D, a resist is coated on the silicon nitride film 34b on the second silicon substrate 32, and the ink intake port 18 is formed by exposure and development.
A resist pattern having the shape of is formed. At this time, the first
The common liquid chamber 8 formed on the silicon substrate 31 and the pattern of the ink intake port 18 are aligned by the IR light so that the positions of the patterns are the same. Since the second silicon substrate 32 is a double-side polished silicon substrate, the IR image can be clearly seen by the transmission type or reflection type IR alignment. Next, the silicon nitride film 3 in the opening of the resist
4b is removed by dry etching to remove the resist.

After that, as shown in FIG. 6A, 25w
The second silicon substrate 32 is anisotropically etched with a t% aqueous solution of potassium hydroxide at a temperature of 90 ° C. to form a part of the through-hole 19 which becomes the ink intake port 18.
With this etching solution, the etching of the (100) plane is 2.
It proceeds at a speed of 5 μm / min. When the etching progresses and reaches the thermal oxide film 2a, the etching is stopped because the etching rate of the thermal oxide film 2a is very small. The anisotropic etching of the (100) plane forms a taper at an angle of 54.7 °. Here, as a result of etching the opening having a width of 1.35 mm in the stage of FIG. 6A, the width at the oxide film 2a reaches 0.5 mm.

Next, a resist is coated on the silicon nitride film 34a on the first silicon substrate 31, and a resist pattern in the shape of the discharge chamber 6 or the common liquid chamber 8 is obtained by exposure and development. At this time, similarly to the above, the alignment is performed by IR light so that the positions of the patterns of the individual electrodes 15 of the second silicon substrate 32 and the ejection chambers 6 of the first silicon substrate 31 match. Then, as shown in FIG. 3B, the silicon nitride film 34a in the opening of the resist is removed by dry etching to remove the resist.

Next, anisotropic etching was performed at a temperature of 85 ° C. with a 30 wt% potassium hydroxide aqueous solution (KOH) to which IPA (isopropyl alcohol) was added in a supersaturated state, as shown in FIG. The first silicon substrate 31 is simultaneously formed with the recesses serving as the discharge chamber 6 and the common liquid chamber 8 and the diaphragm 10 including the high-concentration boron layer 31a.

With this etching solution, the etching of the (110) plane proceeds at a rate of 1.5 μm / min. When the etching progresses and reaches the high-concentration boron layer 31a, the etching rate sharply decreases. However, since the etching is not completely stopped, it is difficult to determine the etching stop.

Therefore, the etching time was set to be 30 minutes longer than the etching time for penetrating the 100 μm low-concentration boron-doped (110) plane Si substrate. IPA added 3
At 0 wt% KOH and 85 ° C, the thickness is 100 μm (11
Since the Si substrate having the (0) plane orientation penetrated in 80 minutes, the etching time was set to 110 minutes. At the end of etching, the etch rate ratio has dropped to 1/150 and the thickness is 2μ.
The vibrating plate 10 of m was obtained. Diaphragm 1 under the above conditions
The thickness of 0 was 2 ± 0.08 μm in 3σ, and the etching surface property was Ra 0.01 μm.

Here, it is preferable to terminate the etching when the etching rate ratio to the (110) plane becomes 1/50 to 1/300 in terms of etching time and etching surface property. Compared to EDP (ethylenediaminepyrocatechol), the decrease in the etching rate with respect to the boron concentration is smaller in the aqueous potassium hydroxide solution. However, when IPA is added to the potassium hydroxide aqueous solution, the boron concentration is lower than that of the potassium hydroxide aqueous solution to which IPA is not added (1
10) Ratio of etch rate of high-concentration boron diffusion layer to etch rate of surface (etch rate of high-concentration boron diffusion layer /
The etch rate of the (110) plane becomes small. Note that I
Since PA has a low boiling point and evaporates significantly when heat is applied, it is preferable to attach a reflux device for cooling the vapor to liquefy it and returning it to the etching tank.

Next, the silicon nitride films 34a and 34b are removed by wet etching or dry etching with hot phosphoric acid or the like. Here, the silicon nitride films 34a and 34b may be left as they are without being removed. Subsequently, by dicing the position indicated by the alternate long and short dash line, the wafer is cut into a chip size.

Thereafter, as shown in FIG. 7A, the metal mask 35 is formed so as to protect the discharge chamber 6 and the common liquid chamber 8.
Then, the high-concentration boron diffusion layer 31a on the electrode pad 15a is removed by dry etching. Then, the insulating film 17 on the electrode pad 15a is also removed by etching by dry etching. This makes the first
The flow path substrate 1 including the silicon substrate 31 is completed.

Next, as shown in FIG. 7B, dry etching is performed from the second silicon substrate 32 side to form the second silicon substrate 3 corresponding to the position of the ink intake port 18.
The thermal oxide film 2a on the second side is removed, and the high-concentration boron diffusion layer 31a in a portion of the first silicon substrate 31 (flow path substrate 1) corresponding to the through hole 19 of the second silicon substrate 32 is removed by etching. Thus, the ink intake port 18 including the through hole 19 is completed. Thereby, the second silicon substrate 32
To complete the electrode substrate 2.

Finally, as shown in FIG. 6C, the nozzle plate 3 having the nozzle 4 and the fluid resistance portion 7 is joined to the flow path substrate 1 formed from the first silicon substrate 31 to thereby form the ink jet head. Is completed.

As described above, since the through-hole serving as the ink inlet is formed by anisotropic etching, a large ink inlet can be manufactured at a low cost, and the second silicon substrate serving as an electrode substrate and the flow channel substrate are formed. Since the through-hole is formed after the first silicon substrate is bonded, the strength of the substrate is increased, it is possible to prevent a decrease in yield such as breakage during the manufacturing process, and it is possible to manufacture the ink intake port with high yield. did it.

The method of forming the through-hole has been described by taking anisotropic etching as an example, but isotropic etching with a hydrofluoric / nitric acid-based etching solution or sandblasting may be used.

Next, an ink jet head according to a second embodiment of the present invention will be described with reference to FIG. It should be noted that this figure is an explanatory plan view of the same head excluding the nozzle plate. In this ink jet head, a through hole serving as an ink inlet formed in the electrode substrate 2 which is the second silicon substrate is divided into a plurality of through holes 39, 39 ... And divided by each through hole 39, 39. The ink inlet is formed.

By dividing the through-hole for supplying ink formed on the second silicon substrate into the plurality of through-holes 39 as described above, the strength of the head is increased, and the FPC cable is pressure-bonded to the individual electrode 15 by pressure bonding. Even in a process such as a process that is easily damaged, the head is not damaged and the yield is improved. Further, even if the through-hole serving as the ink intake port is divided, only a thin divided column is inserted, and therefore, the ink inflow capacity is reduced only slightly, and there is substantially no effect.

Next, FIG. 9 shows the third embodiment of the present invention.
Will be described with reference to. It should be noted that this figure is an explanatory plan view of the same head excluding the nozzle plate. In this inkjet head, the elongated through-hole 19 is formed on the electrode substrate 3 which is the second silicon substrate, as in the first embodiment, while the first through-hole is formed.
In the silicon substrate 1, an opening 38 that connects the through-hole 19 and each discharge chamber 6 is formed by dividing each bit. In this case, the through hole 19 of the electrode substrate 2 substantially functions as a common liquid chamber.

That is, as shown in FIG. 6C, when the second silicon substrate 32 is penetrated by anisotropic etching, a compressive stress is exerted on the thermal oxide film 2a. The thermal oxide film 2a may be broken. In this case, plasma may enter the discharge chamber 6 side from the place where the thermal oxide film 2a is broken by the dry etching which is the subsequent process, and the diaphragm 10 may be etched to change the thickness of the diaphragm 10. .

Therefore, the second silicon substrate 3 is formed by forming a plurality of openings 38 in the first silicon substrate 31, which are divided for each bit and which communicate the respective discharge chambers 6 with the through holes 19.
Even when 2 is penetrated by anisotropic etching, the thermal oxide film 2a is divided into small regions, so that the thermal oxide film 2a is less likely to be broken even if stress is applied. As a result, the discharge chamber 6 is formed by the subsequent dry etching.
It is possible to prevent the plasma from entering the side and prevent the diaphragm 10 from being etched and changing its thickness.

Further, when the vibration plate of a certain discharge chamber is driven to discharge ink, ink vibration may be transmitted to the adjacent discharge chamber via the fluid resistance and the common ink chamber, so-called crosstalk may occur. In the case of the inkjet head of this embodiment, the first silicon substrate is provided between the common liquid chamber formed by the through hole 19 of the electrode substrate 2 which is the second silicon substrate and the fluid resistance portion 7 of the nozzle plate 3. Since there is an individual space (opening 38) formed in a certain flow path substrate 1, there is also an advantage that crosstalk is reduced.

Next, a different example of the fourth embodiment of the present invention will be described with reference to FIGS. It should be noted that each drawing is a view of the electrode substrate of the head according to the same embodiment as seen from the back surface. In this embodiment, a silicon substrate having a (110) plane orientation is used as a second silicon substrate (electrode substrate) on which the individual electrodes 15 constituting the pressure generating means are provided.

First, the first example shown in FIG. 10 is (110)
When anisotropic etching is performed on the electrode substrate 2 which is the second silicon substrate having the plane orientation by aligning the longitudinal direction of the pattern of the hexagonal through-holes 19 with the <110> direction, a pair of hexagonal opposing faces are formed. A (111) tapered surface 19a is formed at an angle of 35.3 ° on each side, and a (111) surface perpendicular to the (110) surface appears on the other four sides.

In this case, since the silicon substrate having the (110) plane orientation is used as the electrode substrate 2 made of the second silicon substrate, the taper in the longitudinal direction of the through hole 19 does not appear, and the margin M to the periphery of the chip is set. The size of the chip itself can be reduced. In this embodiment also, as shown in FIG. 9, it is possible to form openings divided into bits for each bit in the first silicon substrate.

Next, the second example shown in FIG. 11 is (110)
The electrode substrate 2 which is the second silicon substrate having the plane orientation is anisotropically etched with the longitudinal direction of the pattern of the hexagonal through holes 19 aligned with the <112> direction. In this case, a wall in the width direction of the through hole is obtained that is perpendicular to the substrate surface, and (111) taper surfaces 19a appear at both longitudinal ends as shown in FIG.

In this example, since a vertical wall is obtained, if the openings of the through holes are made to be the same, the size of the through holes may be small, the strength of the substrate is increased, and the yield during manufacturing is improved.

Furthermore, the third example shown in FIG.
0) In the electrode substrate 2, which is the second silicon substrate having the plane orientation,
Set the longitudinal direction of the hexagonal through-hole 19 pattern to <011>.
This is anisotropically etched in conformity with the direction, and in this case as well, the wall in the width direction of the through hole is perpendicular to the substrate surface. However, since the vertical wall is composed of the (100) plane, the etching progresses in the lateral direction as well, and the width of the through hole becomes larger than the width of the etching mask. Therefore, the pattern of the etching mask is designed in consideration thereof.

Next, an ink jet head according to the fifth embodiment of the present invention will be described with reference to FIG. In this inkjet head, an oxide film is formed on a (100) or (110) plane base wafer 41 and a (100) plane-oriented bond wafer 42 that form a partition wall of a discharge chamber 6 using a flow path substrate 1 which is a first silicon substrate. A so-called SOI (Silicon on Insulator) substrate bonded through the layer 43 is used.

When a silicon substrate having a (100) plane orientation is used as the base wafer 41, the <110> direction of the base wafer 41 and the <110> direction of the bond wafer 42 having the (110) plane orientation and the second direction When the <110> directions of the electrode substrate 2 which is a silicon substrate are parallel to each other, and when a silicon substrate having a (110) plane orientation is used as the base wafer 41, the <110> plane orientation of the base wafer 41
The 1-12> direction, the <110> direction of the bond wafer 42, and the <110> direction of the electrode substrate 2 which is the second silicon substrate are parallel to each other and bonded.

As a result, the SOI is formed on the first silicon substrate.
Even when the substrate is used, the through hole 19 of the electrode substrate 2 and the SO
Through holes (openings) formed in the bond wafer 42 of the I substrate can be continuously communicated.

Therefore, the manufacturing process of this ink jet head will be described with reference to FIGS. First, as shown in FIG. 3A, as the first silicon substrate to be the flow path substrate 1, a thickness 50 having (110) as a plane orientation is obtained.
A so-called SOI (Silicon on Insulator) substrate in which a bond wafer (silicon layer) 42 is formed on a 0 μm silicon substrate (base wafer) 41 with an oxide film layer 43 interposed therebetween is used.

As a method for forming the silicon layer 42, another silicon substrate is bonded to the oxidized silicon substrate 41, and the bonded silicon substrate is polished to a desired thickness to form the silicon layer 42. A general method for manufacturing an SOI substrate can be used, such as a method of forming a polysilicon layer on the silicon substrate 41 and forming the silicon layer 42, or a method of crystallizing the polysilicon layer to form the silicon layer 42.

Here, two silicon substrates are used as the oxide film layer 4
3 was bonded and the silicon substrate was thinned by polishing to form the silicon layer 42. In particular,
A silicon substrate 41 (base wafer) having a plane orientation of (110) is thermally oxidized to form a 5000 Å oxide film 43,
A silicon substrate (bond wafer) having a plane orientation of (100) was bonded by applying heat of 1200 ° C., and then the bond wafer was thinned to 2 μm by polishing to obtain a silicon layer (bond wafer) 42.

At this time, the <1-12> direction of the base wafer (silicon substrate) 41 having a plane orientation of (110) and the bond wafer (silicon layer) having a plane orientation of (100).
42 was laminated so that the <110> directions of 42 were parallel to each other. The discharge chamber 6 to be formed on the base wafer 41 later has its longitudinal direction formed in the <1-12> direction of the base wafer 41.

On the other hand, the thickness 6 of the double-sided polishing which becomes the electrode substrate 1
Second silicon substrate 32 having a (100) plane orientation of 00 μm
Then, the thermal oxide film 2a is formed, and the recess 14 is formed in the thermal oxide film 2a by etching, and the individual electrode 15, the insulating layer 17 and the like are formed in the recess 14. Here, the longitudinal direction of the recess 14 and the individual electrode 15 formed in the silicon substrate 32 is formed parallel to the crystal direction <110> of the silicon substrate 32.

Then, the silicon substrate 41 is directly bonded to the silicon substrate 32 with the silicon layer 42 side being the bonding surface.
Here, what was pre-bonded under reduced pressure was 100
Bonding was performed by heat treatment at 0 ° C. for 2 hours. At this time, the crystal orientation of the silicon substrate 41 in the (110) plane direction <
Bonding was performed so that −111> and the (100) plane orientation of the silicon substrate 32 were parallel to the crystal direction <110>.

Then, as shown in FIG.
The silicon substrate 41 of 00 μm is thinned by polishing to a thickness of 100 μm. Then, LP-CV is attached to the bonded substrate.
D forms the silicon nitride films 34a and 34b.

Next, a resist is coated on the silicon nitride film 34b on the silicon substrate 32 in FIG. 3C, and a resist pattern in the shape of the ink intake port 18 is formed by exposure and development. This pattern is <1 on the silicon substrate 32.
It has a rectangular shape with one side parallel to the 10> direction. At this time, the common liquid chamber 8 formed on the silicon substrate 41 and the ink intake port 18 are patterned so that the positions of the patterns are the same.
Align with light. Since silicon has a high transmittance for long wavelength light, internal steps and patterns of metal films can be seen by IR light.

However, when the silicon surface is not a mirror surface,
A clear IR image cannot be obtained, making precise alignment difficult. Here, since the silicon substrate 32 is a double-side polished substrate, an IR image can be clearly seen by IR alignment, and accurate alignment is possible.

Further, a single-side polished substrate is used as the silicon substrate 32, and the silicon substrate 3 is bonded to the silicon substrate 41.
2 may be polished, as long as the surface of the silicon substrate 32 is a mirror surface during IR alignment. However, when the through holes are formed in the subsequent silicon substrate 32 by anisotropic etching using an alkaline solution such as an aqueous solution of potassium hydroxide,
Since the taper is formed at an angle of 54.7 ° in the anisotropic etching of the (100) plane, the size of the through hole changes depending on the thickness of the silicon substrate 32. Silicon substrate 3
In consideration of controlling the thickness of the silicon substrate 41
Rather than polishing after bonding with the silicon substrate 32 in advance
It is preferable to polish both sides to control the thickness.

Next, as shown in FIG. 3D, the silicon nitride film 34b in the opening of the resist is removed by etching by dry etching, and the resist is removed by a wet process such as a resist stripping solution or sulfuric acid or an oxygen plasma asher. Remove by dry process.

Then, as shown in FIG.
By anisotropic etching of the silicon substrate 32 with a wt% aqueous solution of potassium hydroxide at a temperature of 90 ° C., a part of the through-hole 19 to be the ink inlet 18 is formed. With this etching solution, the etching of the (100) plane is 2.5 μm /
Proceed at the speed of minutes. Etching progresses and thermal oxide film 2a
When the temperature reaches, the etching is stopped because the etching rate of the thermal oxide film is very low. As described above, one side of the rectangular opening pattern of the silicon nitride film 34b is parallel to the <110> direction of the silicon substrate 32.
In the anisotropic etching of the (0) plane, at an angle of 54.7 ° (1
11) A taper is formed. 1.3 here
As a result of etching the opening having a width of 5 mm, the width of the through hole 19 reaching the oxide film 2a became 0.5 mm.

Next, as shown in FIG. 7B, the oxide film 2a exposed by the through hole 19 is removed by a hydrofluoric acid-based etching solution.

Next, a resist is coated on the silicon nitride film 34a on the silicon substrate 41 in FIG. 9C, and a resist pattern in the shape of the discharge chamber 6 or the common liquid chamber 8 is obtained by exposure and development. At this time, in the same manner as described above, the individual electrodes 15 of the silicon substrate 32 are aligned with the IR light so that the positions of the patterns of the discharge chamber 6 coincide with each other.

At this time, the longitudinal direction of the recess 14 and the individual electrode 15 is formed parallel to the <110> direction of the silicon substrate 32, and the <110> direction of the silicon substrate 32 and the <1-12> direction of the silicon substrate 41 are parallel. Therefore, the discharge chamber 6 inevitably has a longitudinal direction of <1- of the silicon substrate 41.
12> direction.

Then, the silicon nitride film 34a in the opening of the resist is removed by dry etching to remove the resist.

Next, as shown in FIG.
%, The opening of the silicon substrate 41 and the opening of the silicon layer 42 are anisotropically etched with a potassium hydroxide aqueous solution at a temperature of 80 ° C. The opening of the pattern of the discharge chamber 6 of the silicon substrate 41 has a longitudinal direction of <1-1 of the silicon substrate 41.
Since the discharge chamber 6 is parallel to the 2> direction, a vertical partition wall formed by the (111) plane is formed in the longitudinal direction, and the opening of the pattern corresponding to the through hole 19 of the silicon layer 42 is rectangular. Since one side is parallel to the <110> direction of the silicon layer 42, it is possible to perform etching along a rectangle, and a taper forming an angle of 54.7 ° is formed without breaking the etching shape. Rectangular through holes (openings) 19b are obtained in parallel with the arrangement. When the etching of the silicon layer 42 progresses by 2 μm, it reaches the oxide film 43 and the etching stops.

At this time, since the oxide film 2a of the portion exposed by the through hole 19 of the silicon substrate 32 is removed in the step (b) of the figure, the silicon layer 42 is etched from the back surface. Become. By etching only from the surface, the silicon layer 42 remains in the ink intake port 18 at the end, and a step of removing the silicon layer 42 is further required.

Therefore, by etching the silicon layer 42 from the back side in this way, it is possible to penetrate the silicon layer 42 at the same time when the ejection chamber 6 and the diaphragm 10 are formed, so that the number of steps can be reduced and the cost can be reduced.

When etching is further advanced, FIG.
As shown in (a), the etching on the silicon substrate 41 side also reaches the oxide film 43. Subsequently, the exposed portion of the oxide film 43 is removed by etching with a hydrofluoric acid-based etching solution, whereby the ink intake port 18 is removed as shown in FIG.
Penetrates completely.

Then, the silicon nitride films 34a and 34b are formed.
Are removed by wet etching or dry etching with hot phosphoric acid or the like. Here again, the silicon nitride films 34a and 34b may be left as they are without being removed.

Subsequently, by dicing the position shown by the alternate long and short dash line in FIG.

Thereafter, as shown in FIG. 7C, the metal mask 35 is formed so as to protect the discharge chamber 6 and the common liquid chamber 8.
The silicon layer 4 overlying the electrode pad 15a.
2 is removed by dry etching. continue,
The insulating film 17 on the electrode pad 15 is also removed by etching by dry etching.

Finally, as shown in FIG. 3D, the nozzle plate 3 having the nozzle 4 and the fluid resistance 7 is attached to the flow path substrate 1.
The ink jet head is completed by bonding it on top.

In this example, a silicon substrate 41 having a (110) plane orientation is used, but a silicon substrate having a (100) plane orientation can be used. In this case, each of the silicon substrate 41, the silicon layer 42, and the second silicon substrate 32 forming the first silicon substrate <1
By making the 10> directions parallel to each other, the discharge chamber 6, the common liquid chamber 8, and the intake port 18 are respectively (11
It is possible to obtain an etching shape surrounded by a tapered partition wall formed by the surface 1), and it is possible to form a rectangular ink intake port 18 in parallel with the arrangement of the ejection chambers 6.

Further, although the diaphragm thickness is controlled by using the SOI substrate in this example, a similar manufacturing method can be applied to the case where the diaphragm thickness is controlled by etching the ordinary silicon substrate by controlling the time. Can be taken.

Next, an ink jet head according to a sixth embodiment of the present invention will be described with reference to FIGS. 17 and 18 together with its manufacturing process. First, as shown in FIG. 17A, a thickness 50 in the (110) plane direction, which becomes the flow path substrate, is 50.
A high-concentration boron diffusion layer 31a is formed on a 0 μm first silicon substrate 31.

Specifically, the first silicon substrate 31 was washed with ammonia-hydrogen peroxide mixture (liquid temperature 80 ° C.) for 5 minutes and with hydrochloric acid-hydrogen peroxide mixture (temperature 80 ° C.) for 5 minutes, and then 10% thereof was washed. The oxide film on the surface is removed by hydrofluoric acid for 30 seconds, and one surface of the silicon substrate 31 is coated with a coating diffusion source by spin coating.

When the coating diffusion source is applied to the silicon substrate 31 by spin coating as described above, radial thickness unevenness (striation) may occur. In such a case, it is advisable to cover the entire silicon substrate 31 with a lid to cover the entire silicon substrate 31 in order to increase the air flow during spin coating and the humidity of the atmosphere to prevent the coating diffusion source from drying during spin coating. Also,
Due to striation, after driving, B ₂ O ₃
Unevenness may occur on the surface of the high-concentration boron diffusion layer 31a after removing the layer at a pitch of several tens of μm, and a defect may occur at the joining with the second silicon substrate 32 that will be the electrode substrate 2 later. Therefore, it is important to apply it uniformly during spin coating.

As the coating diffusion source, for example, FMK-58, MMK-40, 6MK-37 manufactured by Tokyo Ohka Kogyo,
3M-23 and the like (both are trade names) can be used, but other materials can also be used. Here, the above 3M-23 (trade name) was used as the coating diffusion source. This is a coating diffusion source with a relatively low boron concentration, and since it is dried at room temperature after spin coating, it is not necessary to bake after coating, but when using a coating diffusion source with a high boron concentration, spin coating is required. You had better bake it later.

After the application of the diffusion source, the temperature at which nitrogen was flowed was set to 8
Load in 00 ° C oven. After that, oxygen having a concentration of 2 to 3% is mixed with nitrogen for 10 minutes. This oxygen is used to oxidize and fly away the organic matter contained in the diffusion source. After that, the temperature of the furnace is raised to 1125 ° C. at a rate of 6 ° C./minute, held in that state for 40 minutes, then lowered to 800 ° C. at a rate of 3 ° C./minute, and the silicon substrate 31 is taken out.

Then, as described above, the silicon substrate 31 is used.
After the high-concentration boron diffusion layer 31a is formed, the B ₂ O ₃ layer formed on the surface of the high-concentration boron diffusion layer 31a is removed by hydrofluoric acid. A compound layer of silicon and boron is formed under the B ₂ O ₃ layer, and when it is removed, it can be removed with hydrofluoric acid by oxidizing. Even if the compound layer of silicon and boron is oxidized and removed with hydrofluoric acid in this way, since microroughness is generated on the surface of the silicon substrate 31 in which boron is diffused, it is possible to perform direct bonding later. Can not.

Therefore, further CMP (Chemical-Mechani)
(Cal-Polishing) polishing is performed to remove the compound layer of silicon and boron, and surface properties (surface roughness Ra = 5 nm or less) that can be directly bonded to the surface of the silicon substrate 31 are obtained. In CMP polishing, the outermost surface can be uniformly polished in-plane with a polishing amount of 1000 Å or less, and therefore the change in the high-concentration boron diffusion layer 21a is small. In this case, the diffusion condition for diffusing boron may be determined in consideration of the polishing amount. Alternatively, CMP polishing may be performed after the compound layer of silicon and boron is removed by oxidation and hydrofluoric acid treatment.

On the other hand, as shown in FIG. 9B, a second silicon substrate 32 which will be the electrode substrate 2 is manufactured in another step. Here, a thermal oxide film 2a is formed on a double-side polished second silicon substrate 32 having a crystal plane orientation (100) with a thickness of 600 μm, and the concave portion 14 is formed by etching on the thermal oxide film 2a. Individual electrodes 15 in 14,
The insulating layer 17 and the like are formed. The recess 14 and the individual electrodes 15 are formed so that the longitudinal direction of the discharge chamber is parallel to the crystal axis <110> direction of the second silicon substrate 32 (electrode substrate 2).

Then, these first silicon substrate 31
Are directly bonded onto the second silicon substrate 32. Here, 1000 is obtained by pre-bonding under reduced pressure.
Bonding was performed by heat treatment at 2 ° C. for 2 hours. At this time, the crystal axis <1-12> direction of the first silicon substrate 31 having the crystal plane orientation (110) is parallel to the crystal axis <110> direction of the second silicon substrate 32 having the crystal plane orientation (100). To stick together.

Subsequently, the structure shown in FIG. 17C is obtained through the same steps as those of FIGS. 14C, 14D, 15A and 15B described in the fifth embodiment. obtain.

Next, the exposed portion of the silicon substrate 31 is anisotropically etched at a temperature of 80 ° C. with a 30 wt% potassium hydroxide aqueous solution. Since the high-concentration boron layer 31a is formed on the lower side of the silicon substrate 31, as is well known, the etching rate of the high-concentration boron layer is low. However, in the high-concentration boron layer 31a, the etching rate becomes very small in the low-concentration potassium hydroxide aqueous solution, and therefore, the decrease in the etching rate is small in the high-concentration potassium hydroxide aqueous solution as in this example.

Here, as shown in FIG. 9C, the etching from the nitride film 34a side of the silicon substrate 31 is performed by 80.
2 μm high-concentration boron layer 31a at the time of proceeding μm
Was penetrated by etching from the through hole 19 side. At this time, since the (110) substrate is used as the silicon substrate 31, the longitudinal direction of the through-hole 19 (the direction perpendicular to the paper surface).
Since the crystal axes of the silicon substrate 32 do not coincide with each other, the etching proceeds slightly laterally.

Then, the etching solution is changed to a 30 wt% potassium hydroxide aqueous solution to which IPA (isopropyl alcohol) is added in a supersaturated state, and anisotropic etching is performed at a temperature of 80.degree. With this etching solution, the etching of the (110) plane proceeds at a rate of 1.5 μm / min. When this etching solution reaches the high-concentration boron layer 31a, the etching rate sharply decreases. At the end of etching, the etching rate ratio was reduced to 1/150, and as shown in FIG. 7D, the diaphragm 10 having a thickness of 2 μm was obtained.

At this time, the first portion corresponding to the through hole 19
The silicon substrate 31 is etched from both sides and penetrates. Here, the first silicon substrate 3 having the (110) plane orientation
Since the crystal orientation <1-12> of 1 and the crystal orientation <110> of the second silicon substrate 32 having the (100) plane orientation are parallel to each other, the discharge chamber 6 of the silicon substrate 31 has a longitudinal direction. The partition walls are vertical walls formed by the (111) plane, and the through-hole 19 of the silicon substrate 32 is a rectangle surrounded by the taper formed by the (111) plane.

In the present embodiment, as described above, the etching solution for the first silicon substrate 31 is changed on the way.
That is, the first etching solution was selected so that the etching could proceed even in the high-concentration boron layer. For example, 30w
A high-concentration potassium hydroxide aqueous solution of t% or more is used. Even with a high-concentration potassium hydroxide aqueous solution, the etching rate decreases, but it is possible to etch a high-concentration boron layer having a thickness of about 2 μm. Next, as the second etching solution, an aqueous solution of potassium hydroxide added with IPA or an aqueous solution of low concentration potassium hydroxide, or an etching solution such as EDP having a small etching rate in a high concentration boron layer is selected. When reaching the high-concentration boron layer, the etching rate is rapidly reduced, and only the high-concentration boron layer 31a remains.

Under the above conditions, the thickness of the diaphragm 10 is 3σ.
2 ± 0.08 μm, etching surface property Ra = 0.0
The thickness of 1 μm was obtained. E in potassium hydroxide aqueous solution
Compared to DP (ethylenediaminepyrocatechol), the decrease in etch rate with respect to the boron concentration is small. But,
When IPA is added to the aqueous potassium hydroxide solution, IPA
The etch rate ratio of the high-concentration boron diffusion layer (etch rate of high-concentration boron diffusion layer / etch rate of (110) surface) to the etching rate of the (110) plane having a lower boron concentration than that of the potassium hydroxide solution without addition of Become. Since IPA has a low boiling point and evaporates significantly when heat is applied, it is preferable to attach a recirculation device for cooling the vapor to liquefy it and returning it to the etching tank.

Next, as shown in FIG. 18A, the silicon nitride films 34a and 34b are removed by wet etching with hot phosphoric acid or the like as in the above-described embodiment. Here again, the silicon nitride films 34a and 34b may be left as they are without being removed. Subsequently, by dicing the position indicated by the alternate long and short dash line, the wafer is cut into a chip size.

Thereafter, as shown in FIG. 11B, the metal mask 35 is formed so as to protect the discharge chamber 6 and the common liquid chamber 8.
Then, the boron diffusion layer 31a on the electrode pad 15a is removed by dry etching. Then, the insulating film 17 on the electrode pad 15a is also removed by dry etching.

Finally, as shown in FIG. 11C, the nozzle plate 3 having the nozzle 4 and the fluid resistance portion 7 is bonded to the flow path substrate 1 made of the first silicon substrate 31 to form an ink jet head. Complete.

In this case, the first silicon substrate 31 is used.
Although the substrate having the (110) plane orientation is used for the above, it is also possible to use the silicon substrate having the (100) plane orientation as in the above embodiment. In this case, the first silicon substrate 31 and the second silicon substrate 31
By making the <110> directions of the silicon substrate 32 in parallel with each other, the discharge chamber 6, the common liquid chamber 8, and the ink intake port 18 are each etched in such a shape that they are surrounded by the tapered partition wall formed by the (111) plane. The rectangular ink intake port 18 can be formed in parallel with the arrangement of the ejection chambers 6.

In each of the above embodiments, the present invention is mainly applied to a side shooter type ink jet head in which the displacement direction of the diaphragm and the ink droplet ejection direction are the same. It can be similarly applied to an inkjet head of an edge shooter system that is orthogonal to the droplet discharge direction. In addition, although an example of application to an electrostatic inkjet head that uses electrostatic force between a diaphragm and electrodes as pressure generating means has been described, it is possible to change the volume of the discharge chamber communicating with the nozzle by using a piezoelectric element or the like. The invention can also be applied to a piezo-type inkjet head that ejects ink droplets, or a thermal-type inkjet head that ejects ink droplets by expanding ink in the ejection chamber using a heating element.

[0120]

As described above, according to the ink jet head of the first aspect, the ink is supplied to the second silicon substrate after the second silicon substrate and the first silicon substrate are bonded to each other. Since the through-holes are formed, the substrate strength is increased, and it is possible to prevent a decrease in yield such as breakage during the manufacturing process and to reduce costs.

According to the ink-jet head of the second aspect, in the ink-jet head of the first aspect,
Since the through hole for supplying ink is formed by anisotropic etching, a large ink intake port can be formed at low cost.

According to the ink jet head of the third aspect, the width of the through-hole for supplying ink, which communicates with the common liquid chamber of the second silicon substrate, is smaller than the width of the common liquid chamber of the first silicon substrate. Therefore, even if the wall surface of the common liquid chamber has a saw-tooth shape, the ink flow is not obstructed, and efficient ink supply can be performed.

According to the ink jet head of the fourth aspect, since the second silicon substrate has a plurality of divided through holes for supplying ink, the yield is improved even in a process such as a pressure bonding process which is easily damaged. It can be manufactured well.

According to the ink jet head of the fifth aspect, the second silicon substrate has the through hole for supplying ink, and the first silicon substrate communicates with the through hole for supplying ink and the discharge chamber. Since the opening is formed and the opening is divided into a plurality of portions, it is possible to prevent the oxide film of the second silicon substrate from being damaged when forming the through hole, and reduce crosstalk.

According to a sixth aspect of the present invention, there is provided the ink jet head according to any one of the first to fifth aspects, wherein the second silicon substrate has a (110) plane orientation, so that the through-hole is made of the silicon substrate. By forming it to match <110>, the taper in the longitudinal direction of the through hole does not appear,
It is possible to reduce the margin up to the periphery of the chip, and the wall surface of the through hole becomes vertical to the substrate surface by forming it so as to match the <112> direction, and the size of the through hole can be reduced. The substrate strength is increased and the yield during manufacturing is improved.

According to a seventh aspect of the present invention, there is provided an ink jet head according to any one of the first to fifth aspects, wherein the second silicon substrate has a (100) plane orientation and Since it is formed so as to match the 011> direction, the wall surface of the through hole becomes vertical to the substrate surface, the size of the through hole can be reduced, the substrate strength is increased, and the yield during fabrication is improved. .

According to the ink jet head of the eighth aspect, the through holes for supplying the ink are formed by anisotropic etching in the second silicon substrate having the (100) plane orientation. <1 of the first silicon substrate
Since the <10> direction of the second silicon substrate and the <110> direction of the second silicon substrate are parallel to each other, the discharge chambers can be formed in a shape surrounded by the (111) planes and can be arranged at a high density, and the through holes can also be formed in the (11) direction.
1) It can be formed in a rectangular shape surrounded by the surface, can achieve high density, improve ink supply efficiency, and enable high speed printing by high frequency driving.

According to the ink jet head of the ninth aspect, the through holes for ink supply are formed by anisotropic etching in the second silicon substrate having the (100) plane orientation, and the (110) plane orientation is provided. <1 of the first silicon substrate
Since the −12> direction and the <110> direction of the second silicon substrate are parallel to each other, the discharge chambers can be formed in a shape surrounded by the (111) planes and can be arranged at a high density, and the through holes can also be formed. It can be formed in a rectangular shape surrounded by the (111) plane, which can achieve high density, improve ink supply efficiency, and enable high-speed printing by high-frequency driving.

According to the ink jet head of the tenth aspect, the first silicon substrate is an SOI substrate obtained by bonding a base wafer having a (100) plane orientation and a bond wafer having a (100) plane orientation, and a second silicon substrate. The substrate is a silicon substrate having a (100) plane orientation,
Since the <110> direction of the base wafer, the <110> direction of the bond wafer, and the <110> direction of the second silicon substrate in the plane orientation are parallel to each other, the opening of the bond wafer can be continuously communicated with the through hole. .

According to the ink jet head of the eleventh aspect, the first silicon substrate is the SOI substrate formed by bonding the base wafer having the (110) plane orientation and the bond wafer having the (100) plane orientation, and the second silicon substrate is used. The substrate is a silicon substrate having a (100) plane orientation, and (11
0) plane orientation <1-12> direction of the base wafer, <110> direction of the bond wafer and <11> of the second silicon substrate
Since the 0> directions are parallel, the opening of the bond wafer can be continuously communicated with the through hole.

According to the ink jet head of the twelfth aspect, the through hole for ink supply is formed in the second silicon substrate by anisotropic etching, and the portion corresponding to the through hole of the first silicon substrate is the first hole. Since the opening is formed by anisotropic etching from the bonding surface side of the second silicon substrate, the ink intake port can be formed at the same time by anisotropic etching for forming the ejection chamber, and the manufacturing process can be reduced. The cost can be reduced.

According to the ink jet head manufacturing method of the thirteenth aspect, there is provided the ink jet head manufacturing method of the twelfth aspect, wherein the portion corresponding to the through hole of the first silicon substrate is a high concentration boron layer. In the step of anisotropically etching the first silicon substrate from the bonding surface side with the second silicon substrate, an etching solution with a high etching rate for the high concentration boron layer is first used, and then an etching solution for the high concentration boron layer is continuously used. Since etching is performed sequentially with an etching solution having a small rate, even if a high-concentration boron layer is provided, it is possible to simultaneously form the ink intake port by anisotropic etching for forming the ejection chamber, and it is possible to reduce the manufacturing process. The cost can be reduced.

According to the ink jet head of the fourteenth aspect, since the surfaces of the second silicon substrate and the first silicon substrate are all polished surfaces, the first silicon substrate and the second silicon substrate are An IR image can be clearly obtained at the time of alignment at the time of joining, and precise alignment can be performed, resulting in less variation and improved yield.

[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 a schematic cross-sectional explanatory view along the long side direction of the ejection chamber of the same head.

FIG. 4 is a schematic cross-sectional explanatory view along the short side direction of the ejection chamber of the same head.

FIG. 5 is a schematic cross-sectional explanatory diagram for explaining the manufacturing process of the head.

FIG. 6 is a schematic cross-sectional explanatory view for explaining the process following FIG.

FIG. 7 is a schematic cross-sectional explanatory diagram for explaining the process following FIG.

FIG. 8 is an explanatory plan view of the inkjet head according to the second embodiment of the present invention, excluding the nozzle plate.

FIG. 9 is an explanatory plan view of the inkjet head according to the third embodiment of the present invention, excluding the nozzle plate.

FIG. 10 is an explanatory plan view of a second silicon substrate (electrode substrate) illustrating a first example of an inkjet head according to a fourth embodiment of the present invention.

FIG. 11 is an explanatory plan view of a second silicon substrate (electrode substrate) for explaining a second example of the head.

FIG. 12 is an explanatory plan view of a second silicon substrate (electrode substrate) for explaining a third example of the head.

FIG. 13 is a schematic cross-sectional explanatory view along the long side direction of the ejection chamber of the inkjet head according to the fifth embodiment of the present invention.

FIG. 14 is an explanatory diagram illustrating a manufacturing process of the head.

15 is an explanatory diagram illustrating a step following FIG.

16 is an explanatory diagram illustrating a step following FIG.

FIG. 17 is an explanatory diagram illustrating an inkjet head according to a sixth embodiment of the present invention together with its manufacturing process.

FIG. 18

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flow path substrate, 2 ... Electrode substrate, 2a ... Thermal oxide film, 3 ... Nozzle plate, 4 ... Nozzle, 6 ... Discharge chamber, 8 ... Common liquid chamber, 10
... diaphragm, 15 ... electrode, 18 ... ink intake port, 1
9, 39 ... Through hole, 31 ... First silicon substrate, 31a
... High-concentration boron diffusion layer, 32 ... Second silicon substrate, 3
8 ... Opening, 41 ... Base wafer, 42 ... Bond wafer,
43 ... an oxide film layer.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 18, 2001 (2001.7.1)
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 18

[Correction method] Change

[Correction content]

FIG. 18 is an explanatory diagram explaining a step following FIG. 17;

Claims (14)

[Claims] 1. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. An inkjet head in which a second silicon substrate provided with at least a part of the pressure generating means is bonded, and the first silicon substrate and the second silicon substrate are bonded to each other, and then the second silicon substrate is bonded to the second silicon substrate. An ink jet head having a through hole for supplying ink. 2. The inkjet head according to claim 1, wherein the through hole for supplying the ink is formed by anisotropic etching. 3. A nozzle for ejecting an ink droplet, an ejection chamber communicating with this nozzle, a common liquid chamber communicating with this ejection chamber, and a pressure generating means for pressurizing ink in the ejection chamber, An ink jet head in which a first silicon substrate forming a partition of a chamber and a second silicon substrate provided with at least a part of the pressure generating means are bonded together, and the common liquid chamber is provided in the first silicon substrate. ,
An ink jet head, characterized in that the second silicon substrate has a through hole for supplying ink, which communicates with the common liquid chamber, and the width of the through hole is smaller than the width of the common liquid chamber. 4. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. An ink jet head in which a second silicon substrate provided with at least a part of the pressure generating means is bonded together, and the second silicon substrate has a through hole for supplying ink, and the through hole is divided into a plurality of holes. Inkjet head characterized by being provided. 5. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. And a second silicon substrate provided with at least a part of the pressure generating means, wherein the second silicon substrate has a through hole for ink supply, and the first silicon substrate is provided with An inkjet head having a plurality of divided openings communicating with the through-hole and the discharge chamber. 6. The inkjet head according to any one of claims 1 to 5, wherein the second silicon substrate has a (110) plane orientation, and
An ink jet head, wherein the through-hole is formed so as to match the 110> or <112> direction. 7. The inkjet head according to any one of claims 1 to 5, wherein the second silicon substrate has a (100) plane orientation, and
The inkjet head is characterized in that the through-hole is formed so as to coincide with the 011> direction. 8. A first silicon substrate comprising a nozzle for ejecting an ink drop, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. In the ink jet head in which the second silicon substrate provided with at least a part of the pressure generating means is bonded, the through hole for supplying ink is anisotropically etched in the second silicon substrate having the (100) plane orientation. The <110> direction of the first silicon substrate and the <11> direction of the second silicon substrate having the (100) plane orientation are formed.
An ink jet head characterized in that the 0> directions are parallel. 9. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. In the ink jet head in which the second silicon substrate provided with at least a part of the pressure generating means is bonded, the through hole for supplying ink is anisotropically etched in the second silicon substrate having the (100) plane orientation. An inkjet head, wherein the <1-12> direction of the formed (110) plane orientation of the first silicon substrate is parallel to the <110> direction of the second silicon substrate. 10. A first silicon substrate comprising a nozzle for ejecting an ink drop, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. And a second silicon substrate provided with at least a part of the pressure generating means, in an inkjet head, the first silicon substrate is a (100) plane-oriented base wafer and a (100) plane-oriented bond wafer. It consists of a combined SOI substrate,
The second silicon substrate is a silicon substrate having a (100) plane orientation, and the <110> direction of the base wafer and the <1> of the bond wafer having a (100) plane orientation of the first silicon substrate.
An inkjet head in which the 10> direction and the <110> direction of the second silicon substrate are parallel to each other. 11. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. And a second silicon substrate provided with at least a part of the pressure generating means, in an inkjet head, the first silicon substrate is a (110) plane-oriented base wafer and a (100) plane-oriented bond wafer. It consists of a combined SOI substrate,
The second silicon substrate is a silicon substrate having a (100) plane orientation, and the <1-12> direction of the base wafer and the <1-12> direction of the bond wafer having a (110) plane orientation of the first silicon substrate.
An inkjet head characterized in that the <110> direction and the <110> direction of the second silicon substrate are parallel to each other. 12. A first silicon substrate comprising a nozzle for ejecting an ink droplet, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. In an inkjet head in which a second silicon substrate provided with at least a part of the pressure generating means is bonded, a through hole for ink supply is formed in the second silicon substrate by anisotropic etching, An ink jet head, wherein a portion of the first silicon substrate corresponding to the through-hole is anisotropically etched and opened from a bonding surface side with the second silicon substrate. 13. The manufacturing method for manufacturing an ink jet head according to claim 12, wherein a portion of the first silicon substrate corresponding to the through hole is formed of a high-concentration boron layer. Is a step of anisotropically etching from the bonding surface side with the second silicon substrate, and is sequentially etched with an etching solution having a high etching rate for the high-concentration boron layer first, and then with an etching solution having a low etching rate for the high-concentration boron layer. A method for manufacturing an inkjet head, comprising: 14. A first silicon substrate comprising a nozzle for ejecting ink droplets, an ejection chamber communicating with the nozzle, and a pressure generating means for pressurizing ink in the ejection chamber, and forming a partition wall of the ejection chamber. In an ink jet head in which the above and a second silicon substrate provided with at least a part of the pressure generating means are bonded together, the surfaces of the first silicon substrate and the first silicon substrate are all polished surfaces. Inkjet head.