JP2000117982A - Ink jet head and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate connection of a connecting means with an external circuit without increasing the manufacturing step by arranging an outer electrode for diaphragm in flush with the diaphragm in an ink jet head. SOLUTION: An outer electrode 27 for diaphragm is formed by removing the contact part 26 of a diaphragm substrate 20 except a part for forming the outer electrode 27. In order to remove an electrode protective film 35 on an outer electrode 34 for individual electrode, a nickel outer electrode 34 for individual electrode on an electrode substrate 30 is exposed by dry etching. The outer electrode 27 for diaphragm of same thickness as the diaphragm is thereby made flush with the diaphragm and the level difference can be set within 2 μm between the outer electrode 27 for diaphragm and a plurality of outer electrodes 34 for individual electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head, and more particularly to an ink jet head using electrostatic force and a method of 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, a plotter, etc. has a nozzle hole for discharging ink droplets and a discharge chamber (pressure chamber) communicating with the nozzle hole. , A pressurized liquid chamber, a liquid chamber, an ink flow path, etc.) and energy generating means for generating energy for pressurizing the ink in the discharge chamber. An ink-on-demand system that discharges ink droplets from a nozzle hole by pressurizing indoor ink and discharges ink droplets only when recording is necessary is the mainstream.

Conventionally, as an energy generating means for generating energy to pressurize ink in a discharge chamber, a piezoelectric element is used to deform a diaphragm forming a wall surface of the discharge chamber to change the volume of the discharge chamber to discharge ink droplets. (See JP-A-2-51734), or an ink droplet is ejected by pressure generated by heating ink in an ejection chamber using a heating resistor to generate bubbles. Japanese Patent Application Laid-Open No. 61-59911) is known.

[0004] However, in the conventional method using the piezoelectric element among the above-mentioned conventional inkjet heads, the step of attaching the chip of the piezoelectric element to the vibrating plate in order to generate pressure in the discharge chamber is complicated. High-speed, high-printing quality is demanded for inkjet recording devices, and in order to respond to this, multi-nozzles and high-density nozzles are indispensable. Adhering to the diaphragm is extremely complicated and takes a lot of time. Moreover, as a result of the high density,
Although it has become necessary to process the piezoelectric element with a width of several tens to one hundred and several tens of micrometers, variations in the processing quality occur in the dimensions and shape accuracy in conventional mechanical processing, so that the printing quality varies greatly.

[0005] In the latter method of heating ink, no problem occurs when a piezoelectric element is used.
The heating resistor is damaged by the rapid heating and cooling of the heating resistor, and the impact when the bubble disappears, so that the life of the inkjet head is generally shortened.

In order to solve such a problem, as described in Japanese Patent Application Laid-Open No. 6-71882, a diaphragm forming a wall surface of a discharge chamber is deformed by electrostatic force (electrostatic force) to discharge. An inkjet head that ejects ink droplets by changing the volume of a room has been proposed, and the method using the electrostatic force has the advantages of achieving small size, high density, high printing quality, and long life.

In an ink jet head using electrostatic force, a voltage is applied from an external circuit to the vibration plate and electrodes arranged opposite to the vibration plate in order to cause the vibration plate to be deformed by the electrostatic force. Must.

Therefore, as described in, for example, JP-A-9-307218, a diaphragm and a first substrate forming a liquid chamber and a second substrate forming an electrode are joined to form a diaphragm. An external electrode for the electrode is provided on the upper surface of the first substrate, and an external electrode for the electrode (external electrode for the individual electrode) is formed in the concave portion of the second substrate. Since a step corresponding to the thickness of the first substrate is generated between the external electrode and the external electrode, it has been proposed to connect to an external circuit using a special FPC cable whose tip is branched into two. .

[0009]

However, as described above, since the external electrode for the diaphragm and the individual electrode must be connected by a special FPC cable whose tip is branched into two, the connection work is troublesome. Work efficiency is poor and F
There is a problem that the cost of the PC itself is also increased, resulting in an increase in the cost of the head.

In the case where the pitch of the diaphragm and the electrodes is reduced in order to increase the density of the ink jet head, for example, after forming the diaphragm by anisotropic etching using an Si substrate as a substrate for producing the diaphragm, However, there is a risk that the attempt to join with the electrode substrate may cause a decrease in yield due to poor joining or breakage of the diaphragm, and there is a problem that alignment and joining times are large and mass productivity is low.

Further, when an Si substrate is used as an electrode substrate and an N-type or P-type impurity layer is used as an electrode (see the above-mentioned Japanese Patent Application Laid-Open No. 6-71882), a metal film which may generate particles during film formation is used. As compared with the case of using a thin film, there is an advantage that a narrow gap can be easily formed between the diaphragm and the electrode, and a high-quality thermal oxide film can be formed as an electrode protective film on the electrode. Due to the occurrence of punch-through between electrodes, reliability is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an ink jet head having an external electrode capable of easily connecting a connecting means to an external circuit without increasing the number of steps, and having a high density. It is intended to provide a manufacturing method thereof.

[0013]

In order to solve the above-mentioned problems, an ink jet head according to claim 1 has a configuration in which external electrodes for a diaphragm are provided on the same plane as the diaphragm.

According to a second aspect of the present invention, in the inkjet head of the first aspect, a step between the external electrode for the diaphragm and the external electrode for the individual electrode is within 2 μm.

According to a third aspect of the present invention, in the ink jet head of the first or second aspect, the external electrodes for the diaphragm and the external electrodes for the individual electrodes are arranged substantially in a line.

According to a fourth aspect of the present invention, in the ink jet head according to any one of the first to third aspects, the diaphragm and the external electrode for the diaphragm are formed on the first substrate, and the electrode and the external electrode for the individual electrode are formed on the first substrate. Formed on the second substrate, at least a region of the first substrate including a region corresponding to the external electrode for the individual electrode of the second substrate was removed except for the external electrode for the diaphragm.

According to a fifth aspect of the present invention, in the ink jet head according to any one of the first to third aspects, the diaphragm and the external electrode for the diaphragm are formed on the first substrate, and the external electrode portion for the diaphragm is formed on the first substrate. The configuration was such that a metal layer was formed.

According to a sixth aspect of the present invention, in the inkjet head of the fifth aspect, the metal layer of the external electrode portion for the diaphragm has a multilayer structure.

According to a seventh aspect of the present invention, in the inkjet head according to the sixth aspect, a layer of the metal layer which contacts the first substrate is made of a metal capable of making ohmic contact with silicon.

An ink jet head according to an eighth aspect of the present invention is the ink jet head according to the sixth or seventh aspect, wherein the outermost surface layer of the metal layers is made of a metal having resistance to halogen-based etching active species.

According to a ninth aspect of the present invention, there is provided a method for manufacturing an ink jet head for manufacturing the ink jet head according to any one of the first to eighth aspects, wherein a diaphragm and an external electrode for the diaphragm are formed. After bonding the first substrate and the second substrate forming the electrodes and the external electrodes for individual electrodes at a predetermined interval between the diaphragm and the electrodes, the diaphragm is formed on the first substrate. In the first substrate, at least a region corresponding to a region including the external electrode for the individual electrode of the second substrate and a contact portion including a portion forming the external electrode for the diaphragm have the same thickness as the diaphragm. And a step of removing a region of the contact portion other than the region where the diaphragm external electrode is to be formed.

According to a tenth aspect of the present invention, in the manufacturing method of the ninth aspect, the first substrate comprises a single-crystal silicon substrate, the second substrate comprises a glass substrate, and the first substrate comprises By forming a gap spacer of the SiO ₂ film or forming a concave portion in the second substrate, a predetermined interval is formed between the diaphragm and the electrode,
The first substrate and the second substrate were configured to be anodic-bonded.

According to an eleventh aspect of the present invention, in the manufacturing method of the ninth aspect, both the first substrate and the second substrate are made of a single-crystal silicon substrate, and the first substrate and / or the second substrate are made of a single-crystal silicon. The first substrate and the second substrate are directly bonded to each other by forming a gap spacer of an SiO ₂ film on the _second substrate and forming a predetermined space between the diaphragm and the electrode. .

According to a twelfth aspect of the invention, there is provided a method of manufacturing an ink jet head according to any one of the ninth to eleventh aspects, wherein prior to the step of removing a portion of the contact portion other than the portion for forming the diaphragm external electrode. In addition, a protective film having resistance to etching is formed on a portion where the external electrode for the diaphragm is to be formed.

According to a thirteenth aspect of the present invention, there is provided a method of manufacturing an ink jet head according to any one of the ninth to eleventh aspects, wherein the step of removing a portion of the contact portion other than the portion for forming the diaphragm external electrode is performed. In addition, a protective film having resistance to etching is formed in a region other than a region removed by etching of the first substrate.

According to a fourteenth aspect of the present invention, there is provided a method for manufacturing an ink jet head according to the twelfth or thirteenth aspect.
X is the short side of the opening of the diaphragm, y is the short side of the contact,
When the thickness of the first substrate is a, at least (a / x)
> 1, (a / y) <1.

According to a fifteenth aspect of the present invention, in the manufacturing method of the ninth to fourteenth aspects, the diaphragm external electrode of the contact portion is formed when the first substrate is etched. The configuration is such that a portion between the portion and the external electrode for individual electrode adjacent thereto is left.

According to a sixteenth aspect of the present invention, in the method of the fifteenth aspect, the short side of the opening of the diaphragm is x, the short side of the contact is y, the external electrode for the diaphragm is provided. When the short side of z is z and the thickness of the first substrate is a, at least (a / x)> 1,
(A / z)> 1, and (a / y) <1.

According to a seventeenth aspect of the present invention, in the method for manufacturing an ink jet head according to the ninth aspect, a portion of the electrode formed on the second substrate facing the diaphragm is a P-type or N-type impurity layer. , A heat-resistant film having high heat resistance is formed in a sheet shape on the contact portion, and a connection hole between the impurity layer and the metal film is arranged between the two.

The method for manufacturing an ink jet head according to claim 18 is the method for manufacturing an ink jet head according to any one of claims 1 to 8, wherein the vibration plate and the external electrode for the vibration plate are formed. After bonding the second substrate forming the electrodes and the external electrodes for the individual electrodes to the silicon wafer serving as the first substrate, the diaphragm and the second plate are formed when forming the flow path pattern including the discharge chamber by etching on the first substrate. After cutting the silicon wafer into individual head chips, leaving a region corresponding to the region including the external electrode for the individual electrode of the second substrate and a contact portion including a portion for forming the external electrode for the diaphragm, The region corresponding to the external electrode for individual electrode was removed.

According to a nineteenth aspect of the present invention, in the manufacturing method of the eighteenth aspect, when the external electrode for the diaphragm is formed, the portion where the external electrode for the diaphragm is to be formed is made in comparison with silicon. The metal layer having a low etching rate was formed.

According to a twentieth aspect of the present invention, there is provided a method of manufacturing an ink jet head according to any one of the ninth to nineteenth aspects, wherein an etching mask made of a material that does not generate a product in an etching process is used as an etching mask.

According to a twenty-first aspect of the present invention, in the method of the twentieth aspect, the material of the etching mask is quartz.

According to a twenty-second aspect of the present invention, in the method of manufacturing the ink jet head of the twenty-first aspect, the material of the etching mask is alumina.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory cross-sectional view illustrating a basic configuration of an electrostatic inkjet head to which the present invention is applied, and FIG. 2 is an explanatory plan view of FIG. The inkjet head includes a first substrate 1, a cover member 2 provided on the upper side of the first substrate 1, an electrode substrate 3 provided on a lower side of the first substrate 1, a first substrate 1, A nozzle plate 4 provided on the front side of the lid member 2.

The first substrate 1 has an ink discharge groove 6 communicating with a plurality of nozzle holes 5 formed in the nozzle plate 4, a concave portion 8 forming a discharge chamber 7 communicating with each ink discharge groove 6, A deformable vibration plate 10 serving as a bottom portion of the discharge chamber 7 and forming a wall surface thereof, and a concave portion 12 forming a common ink flow path 11 for supplying ink to each discharge chamber 7 are provided. In addition, the lid member 2 has an ink supply path 13 also serving as a fluid resistance section that communicates each ejection chamber 7 with the common ink flow path 11, and an ink supply path for supplying ink to the common ink flow path 11 from outside. A mouth 14 is provided. Further, the electrode 1 opposing the diaphragm 10 with a predetermined gap on the electrode substrate 3.
The actuator 17 is constituted by the electrode 17 and the diaphragm 10.

In this ink-jet head, when a driving voltage is applied between the diaphragm 10 and the electrode 17, the diaphragm 10 is deformed by electrostatic force (electrostatic force), and the inner volume of the discharge chamber 7 changes. As a result, ink droplets are ejected from the nozzle holes 5.

An embodiment in which the present invention is applied to such an electrostatic ink jet head will be described with reference to FIG. In the following description, for simplicity of illustration, a liquid chamber or a nozzle hole formed on a diaphragm substrate, or a liquid chamber forming member formed with a liquid chamber or a nozzle to be joined on the diaphragm substrate is illustrated. Is omitted.

The plane orientation (110) in which a high-concentration boron layer capable of spontaneously performing an etch stop by anisotropic etching with KOH is formed on a diaphragm substrate serving as a first substrate forming a diaphragm. In the following, an example will be described in which a glass substrate is used as the second substrate on which the Si substrate is used and the electrode substrate is formed, but the present invention is not limited to these substrates. For example, an SOI substrate may be used as the diaphragm substrate,
The etching for forming the diaphragm may be performed by dry etching, and a Si substrate may be used as the electrode substrate.

First, the first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 3 is a top view of the diaphragm substrate before bonding to the electrode substrate, FIG. 4 is a cross-sectional explanatory view taken along the line AA of FIG. 3 illustrating a manufacturing process of the diaphragm substrate, and FIG. FIG. 6 is a top view of the electrode substrate before bonding to the substrate, and FIG.
FIG. 7 is a cross-sectional explanatory view taken along the line B, FIG. 7 is a top view of a state in which a diaphragm is formed by joining a diaphragm substrate and an electrode substrate, and FIG. 8 is a cross-sectional view of FIG. FIG. 9 is a top view showing a state in which external electrodes are formed on the diaphragm substrate, and FIG. 10 is a cross-sectional explanatory view taken along line DD of FIG. 9 illustrating a manufacturing process for forming the external electrodes. It is.

Referring to FIG. 3 and FIG. 4, the manufacturing process of the diaphragm substrate 20 before bonding will be described. In the case where the diaphragm 25 having a desired thickness (for example, 3 μm) is formed, FIG.
As shown in (a), a high-concentration boron layer 22 of 3 μm is formed on a Si substrate 21 as a first substrate as a diaphragm substrate through an implantation step, an impurity diffusion step, and the like, and thereafter, for example, an LPCVD -A SiN film 23 is formed on the front and back surfaces. In addition, as an etching mask,
For example, a SiO ₂ film may be used, or a stacked film of a SiO ₂ film and a SiN film may be used.

Next, as shown in FIG. 4B, a photoresist 24 is patterned on the Si substrate 21 so that the diaphragm 25 and the contact portions 26 are Si-etched as shown in FIG. As shown in (1), the SiN film 23 on the patterning surface and the SiN film 23 on the entire back surface are etched and removed, and then the photoresist 24 is removed. Thereby, as shown in FIG. 3, the pattern in which the diaphragm 25 and the contact portion 26 are formed on the Si
The diaphragm substrate 20 formed of the N film 23 is obtained.

Here, the contact portion 26 is, as shown in FIG. 7 to be described later, a region corresponding to a region including the individual electrode external electrode 34 of the plurality of electrodes 33 formed on the electrode substrate 30 and a diaphragm plate. It refers to a portion where an external electrode is formed. The contact portion 26 may be a region having a size larger than a region including the plurality of external electrodes for individual electrodes 34.

Next, a manufacturing process of the electrode substrate 30 before bonding will be described with reference to FIGS. 5 and 6. As shown in FIGS. 5 and 6A, a glass substrate as a second substrate is formed. A diaphragm 25 disposed opposite to the diaphragm 31 as described later
A concave portion (hereinafter, referred to as a “gap”) 32 is formed in order to obtain a predetermined gap (interval distance) between the electrode and the electrode 33. The gap 32 is formed by forming a pattern corresponding to the gap 32 on the glass substrate 31 and etching it to a depth of 0.5 μm with hydrofluoric acid, for example.

Then, as shown in FIG. 5 and FIG. 6B, an electrode 33 and an external electrode 34 for an individual electrode continuous with the electrode 33 are formed in the gap 32. These electrodes 33, 3
4 can be formed by depositing a metal that can become an electrode, for example, nickel to a thickness of, for example, 0.2 μm by, for example, a sputtering method, and then patterning by using a photolithography technique.

Here, nickel is used as the metal forming the electrodes 33 and 34, but aluminum or gold can also be used, and the material is not particularly limited. For example, metal materials such as Al, Cr, and Ni generally used in a normal semiconductor element forming process, Ti,
A high melting point metal such as TiN or W, or a polycrystalline silicon material whose resistance is reduced by impurities can be used.
When a silicon substrate is used as the second substrate 2, an impurity diffusion region can be used. At this time, the impurity used for the diffusion is an impurity having a conductivity type opposite to the conductivity type of the substrate silicon. To form a pn junction to electrically insulate the electrodes 33 and 34 from the second substrate 2.

Thereafter, as shown in FIGS. 5 and 6C, an insulating electrode protection film 35 is formed on the surface of the electrode 33 and the external electrode 34 for individual electrodes. Here, as an electrode protection film, for example, a SiO ₂ film 35 is formed with a thickness of, for example, 0.1 μm by, for example, a sputtering method, and then patterned by using a photolithography technique. As a result, as shown in FIG.
Thus, the electrode substrate 30 on which the electrodes 33 covered with 5 and the external electrodes for individual electrodes 34 are formed is obtained.

Therefore, referring to FIGS. 7 and 8, diaphragm substrate 2 shown in FIGS.
Steps from the bonding of the electrode substrate 30 to the vibration plate formation will be described. First, as shown in FIG. 8A, the diaphragm substrate 20 and the electrode substrate 30 are connected to each other by, for example, 40
Joining is performed under the conditions of 0 ° C. and 500 V applied. In this state, the diaphragm 25 of the diaphragm substrate 20 (actually before the diaphragm is formed) and the electrode 33 of the electrode substrate 30 face each other at a predetermined interval, and the contact of the diaphragm substrate 20 is formed. The portion 26 and the plurality of individual electrode external electrodes 34 of the electrode substrate 30 face each other.

Thereafter, as shown in FIG.
Using the LPCVD-SiN film 23 of the diaphragm substrate 20 as a mask with a liquid, the Si substrate 21 as the first substrate is anisotropically etched, so that the etching rate of the high-concentration boron layer 22 is sharply reduced. A diaphragm 25, which is a high-concentration boron layer 22 having a thickness of 3 μm, and a contact portion 26 are accurately formed on the plate substrate 20. Then, the LPCVD used as an etching mask of the diaphragm substrate 20 is performed.
The SiN film 23 is removed.

As a result, as shown in FIG. 7, the diaphragm 25 of the diaphragm substrate 20 and the electrode 33 of the electrode substrate 30 face each other at a predetermined interval, and the contact portion 26 of the diaphragm substrate 20 and the electrode substrate A joining member including the diaphragm substrate 20 and the electrode substrate 30 joined in a state where the plurality of 30 individual electrode external electrodes 34 face each other is obtained.

Therefore, referring to FIGS. 9 and 10, a diaphragm external electrode 27 is formed on the joining member composed of the diaphragm substrate 20 and the electrode substrate 30 obtained in the above-described steps, and the external electrode for the individual electrode is formed. The step of exposing the electrode 34 will be described. In this case, the production of the diaphragm external electrode 27 and the exposure of the individual electrode external electrode 34 are simultaneously performed on the contact portion 26 of the diaphragm substrate 20 by Si etching, but the Si etching is wet etching. Since the etching liquid enters the gap 32, dry etching is preferable. Here, the description will be made on the premise of dry etching.

First, as shown in FIG. 10A, the diaphragm external electrode 27 remains on the diaphragm substrate 20 in a desired region of the contact portion 26 of the diaphragm substrate 20 during Si etching. it only contact portion 26 other than the sets for etching metal mask 36 forming the pattern as Si etching, as shown in FIG. (b), for example, by using a gas to the SF ₆ mainly Si
Perform dry etching.

As a result, as shown in FIGS. 9B and 9, portions of the contact portion 26 of the diaphragm substrate 20 other than the portion where the diaphragm external electrode 27 is formed are removed, and the diaphragm is removed. External electrode 27 is formed. Further, subsequently, an electrode protection film (SiO ₂₎ on the individual electrode external electrode 34 is formed.
In order to remove the film 35, for example, by performing SiO ₂ dry etching using a gas mainly composed of CHF ₃ , the nickel external electrode 3 of the electrode substrate 30 is formed.
4 is exposed. Here, the depth of the gap 32 between the diaphragm external electrode 27 and the individual electrode external electrode 34 is 0.5 μm.
m, since the thickness of the electrode 34 is 0.2 μm,
m.

In this case, since the diaphragm external electrode 27 is formed of the high-concentration boron layer 22, an ohmic contact with, for example, an FPC electrode can be obtained without coating a metal. The process can be completed.
However, in this case, it is more preferable that the metal is coated on the diaphragm external electrode 27. Therefore, as shown in FIG. 10C, the pattern is formed such that only the diaphragm external electrode 27 is coated with metal. The deposited metal mask 37 is set, and gold 28 and the like are formed by, for example, a resistance heating vapor deposition method, thereby completing the manufacturing process.

Thus, the diaphragm external electrode 27 having the same thickness as the diaphragm 25 is provided on the same plane as the diaphragm 25,
An inkjet head (actuator section) can be obtained in which the step between the diaphragm external electrode 27 and the individual electrode external electrodes 34 of the plurality of electrodes 33 is within 2 μm.

As described above, by providing the diaphragm external electrode on the same plane as the diaphragm, the step between the diaphragm external electrode and the individual electrode external electrode can be reduced, and the vibration can be reduced within the small step. Since the plate external electrode and the individual electrode external electrode are arranged, the diaphragm and the electrode can be easily connected to an external circuit by a connection means including a lead wire such as an FPC.

Here, the diaphragm external electrode having the same thickness as the diaphragm is provided on the same plane as the diaphragm, and the step between the diaphragm external electrode and the individual electrode external electrode is set within 2 μm. The step of the external electrode for electrodes is extremely small,
A connecting means including a lead wire such as an FPC can be easily connected, and the diaphragm and the electrode can be easily connected to an external circuit.

Further, by arranging the external electrodes for the diaphragm and the external electrodes for the individual electrodes substantially in a line, the external electrodes for the diaphragm and the external electrodes for the individual electrodes can be collectively connected using the connection means. The connection work can be facilitated, and there is no need to use a special connection means having a tip portion branched into two as in the conventional case, so that there is no increase in cost.

When the diaphragm external electrode and the individual electrode external electrode are formed as in the above embodiment, the diaphragm external electrode is opposed to the diaphragm with respect to the individual electrode external electrode. 0.5 μm). The opposing distance between the diaphragm and the electrode should be formed within a practical range of 2 μm or less as the driving voltage can be reduced if the diaphragm is made as narrow as possible while maintaining the distance where the diaphragm can be displaced. Therefore, the external electrode for the diaphragm and the external electrode for the individual electrode can be easily set within the step of 2 μm or less.

In this case, the diaphragm and the external electrode for the diaphragm are formed on the first substrate, and the electrode and the external electrode for the individual electrode are formed on the second substrate.
By forming a region including at least a region corresponding to the external electrode for an individual electrode of the second substrate of the first substrate is removed while leaving the external electrode for the diaphragm, Since the diaphragm can be formed after the first substrate and the second substrate are joined, it is possible to avoid a decrease in yield due to poor bonding or breakage of the diaphragm, and to form an external electrode for the diaphragm. And the external electrodes for individual electrodes can be simultaneously exposed.

As described above, the first substrate on which the diaphragm and the external electrode for the diaphragm are formed and the second substrate on which the electrode and the external electrode for the individual electrode are formed are placed between the diaphragm and the electrode. After forming the diaphragm on the first substrate after bonding at a predetermined interval, the first substrate corresponds to at least a region of the second substrate including the plurality of external electrodes for individual electrodes. A contact portion having the same thickness as the diaphragm including the region to be formed and the portion for forming the diaphragm external electrode is formed by etching, and portions of the contact portion other than the portion for forming the diaphragm external electrode are removed. By forming the diaphragm external electrode, the diaphragm external electrode having the same thickness as the diaphragm is provided on the same plane as the diaphragm without increasing the number of steps, and the step between the diaphragm external electrode and the individual electrode external electrode is reduced. Within 2 μm, F
It is possible to obtain an ink jet head that can be easily connected to an external circuit by connecting means including a lead wire such as a PC.

In this case, a single crystal silicon substrate is used as the first substrate and a glass substrate is used as the second substrate, and a concave portion is formed in the second substrate, and a predetermined space is formed between the diaphragm and the electrode. in the condition being, the first substrate and the second substrate by anodic bonding, it can also joining the first substrate and the second substrate, or the SiO ₂ film on the first substrate The first substrate and the second substrate can be joined by forming a gap spacer so that a predetermined interval is formed between the vibration plate and the electrode. It is possible to obtain an ink jet head that can be easily connected to an external circuit by the connecting means without increasing the number of ink jet heads.

Further, a single-crystal silicon substrate is used for both the first substrate and the second substrate, and the first substrate or the second substrate, or both the first substrate and the second substrate are used. , A SiO ₂ film gap spacer is formed, and a predetermined space is formed between the diaphragm and the electrode.
Can be directly bonded to the second substrate, and even in this case, an ink jet head that can be easily connected to an external circuit by the connection means without incurring the above-described increase in the number of steps can be obtained. In addition, it is possible to avoid etching defects called latent scratches that may occur when a glass substrate is used, and to form a narrow gap with high accuracy.

Next, a second embodiment of the present invention will be described. The second embodiment is the same as the first embodiment up to the step of forming the diaphragm, and only the method of forming the external electrodes thereafter is different.

That is, when a metal film is coated on the diaphragm external electrode 27, a metal mask 37 for deposition as shown in FIG. 10C is used before performing Si etching on the contact portion 26. A portion of the contact portion 26 to be left as the diaphragm external electrode 27 is coated with gold 28 as a metal film (protective film) having etching resistance to Si etching.
6 is etched to remove portions other than the diaphragm external electrode 27, thereby forming the diaphragm external electrode 27 and removing the electrode protection film 35 of the individual electrode external electrode 34.

This is because, in the Si dry etching using the etching metal mask 36, side edges under the mask tend to occur due to the structure of the sample, and it becomes difficult to leave the diaphragm external electrode 27 with good controllability. There is. Therefore, by coating in advance with a metal film (protective film) having etching resistance to Si etching, the etching margin of the diaphragm external electrode 27 is increased.

In this case, metals having etching resistance to silicon etching include aluminum, nickel and the like in addition to the above-described gold. Further, it is preferable to wash with a HF-based etchant as soon as possible before forming the metal film, so that an insulating film such as a natural oxide film is interposed between the diaphragm external electrode 27 and the metal film (protective film). The probability of contact can be reduced, and a better ohmic contact can be obtained.

Before the step of removing the portion of the contact portion other than the portion where the diaphragm external electrode is to be formed, a protective film having resistance to etching is formed on the portion where the diaphragm external electrode is to be formed. By forming the film, the portion on which the protective film is formed remains without being reliably etched, so that an etching margin is increased with respect to the etching of the contact portion for forming the diaphragm external electrode, and the metal film ( It is also possible to wash with an HF-based etchant before forming the protective film), preventing the insulating film from intervening between the external electrode for the diaphragm and the metal film, and enabling good ohmic contact. become.

Next, a third embodiment of the present invention will be described with reference to FIG.
1 and FIG. FIG. 11 is a top view showing a state in which external electrodes are formed on the diaphragm substrate, and FIG. 12 is a sectional view taken along line EE of FIG. 11 for explaining a manufacturing process of forming the external electrodes. Also in the third embodiment,
Before performing Si etching on the contact portions 26 of the diaphragm substrate 20, the Si substrate is covered with a protective film (metal film) having etching resistance to silicon etching, including a portion left as a diaphragm external electrode. I have to.

That is, first, FIG.
After the step of forming the diaphragm in (b), immediately after forming the metal film as much as possible, after cleaning with an HF-based etchant, the Si substrate 21 is removed as shown in FIGS. Using a metal mask for deposit 38 in which a pattern is formed so that the metal is coated on the entire surface of the contact portion 26 other than the silicon-removed region.
8 is coated.

Next, as shown in FIG.
Si dry etching is performed using a gas mainly composed of F ₆ to remove portions of the contact portion 26 of the diaphragm substrate 20 other than the portion where the diaphragm external electrode 27 is formed. Subsequently, in order to remove the protective film (SiO ₂ film) 35 on the individual electrode external electrode 34 of the electrode substrate 30, for example, CHF
_The SiO ₂ dry etching is performed using a gas mainly composed of ₃ to expose the external electrodes 34 for individual electrodes.

At this time, in the first and second embodiments,
Although the etching has been performed using the etching metal mask 36, since the entire surface of the contact portion 26 other than the silicon removal region is covered with the gold 28 having etching resistance, etching can be performed without a mask. Become.

As described above, before the step of removing the portion of the contact portion other than the portion on which the diaphragm external electrode is to be formed, protection of the first substrate other than the portion removed by etching is performed. With a structure in which a film is formed, etching can be performed without a mask, the number of masks can be reduced by one, cost and process can be reduced, and reduction in yield due to misalignment can be suppressed.

When a metal material which is a highly rigid material is used as a liquid chamber material formed on the diaphragm substrate, a metal film having an etching resistance may be used for eutectic bonding, pressure bonding, solder bonding, brazing, or the like. If a material to be used is also selected, there are effects such as simplification of the diaphragm-liquid chamber joining process and facilitation of joining. As a metal material meeting the above conditions,
There are gold, silver, steel, nickel and the like. Further, since the portion in contact with the ink is covered with a chemically stable metal, there is an effect that the ink is not eroded and the liquid contact property is good.

Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is another example in which etching can be performed without using a metal mask 37 for etching without using a mask. That is, as shown in FIGS. 9 and 10, the short side of the diaphragm 25 (opening) is x, the short side of the contact part 26 (opening) is y, and the thickness of the diaphragm Si substrate 21 is When the contact portion 26 is etched in the structure as shown in FIG. 10B, the thickness a of the Si substrate is large (typically several hundred μm), and the microloading effect is remarkably exhibited. . When the short side y of the contact portion 26 is changed using the applicant's standard RIE apparatus, if a / y is considered as the aspect ratio, the silicon is etched off with an aspect ratio of 0.3 or less under Si 3 μm etching conditions. However, when the aspect ratio was 0.6 or more, almost no etching was performed.

As a result, at least a / a
A configuration that satisfies the relationship of x> 1, a / y <1
When the base 21 is formed, it has been confirmed that etching can be performed without a mask. The above relational expression is almost applicable to a standard RIE apparatus, but is not considered to apply to a high-density plasma etching apparatus which has recently been introduced as a mass production apparatus.

However, since a high-density plasma etching apparatus is much more expensive than a standard RIE apparatus, a standard RIE apparatus which is inexpensive and has a good track record of mass production and which can be etched without a mask is effective in reducing costs. . If the apparatus has both a high-density plasma etching chamber and a standard RIE etching chamber, a combination in which the diaphragm 25 is etched by high-density plasma and the contact portion 26 is etched by standard RIE is also considered. Can be

It is needless to say that the diaphragm external electrode 27 formed in the contact portion 26 is coated with a metal film having etching resistance to silicon etching before the contact portion 26 is etched.

As described above, the short side of the opening of the diaphragm is x,
Assuming that the short side of the contact portion is y and the thickness of the first substrate is a, at least the relationship of (a / x)> 1 and (a / y) <1 is satisfied. Etching can be performed without a mask, the number of masks can be reduced by one, cost and process can be reduced, and reduction in yield due to misalignment can be suppressed. Further, it is possible to prevent side etching under the mask and contamination of the joint surface with the liquid chamber member, which may occur when the contact portion is etched.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
3 and FIG. FIG. 13 is a top view showing a state in which external electrodes are formed on the diaphragm substrate, and FIG. 14 is a sectional view taken along the line FF of FIG. 13 for explaining a manufacturing process for forming the external electrodes. In this embodiment, the diaphragm external electrode 27 formed in the contact portion 26 can be formed with good dimensional controllability.

That is, first, as shown in FIG. 14A, the diaphragm external electrode 27 and the diaphragm external electrode
The etching mask L is used to prevent the etching when forming the diaphragm 25 from being performed between the external electrode 34 for the individual electrode closest to the external electrode 34 (referred to as “34A”).
The PCVD-SiN film 23 is also patterned, and thereafter, as shown in FIG.
Of the diaphragm 25 and the contact portions 26
To form As a result, the pillars 39 of Si remain between the diaphragm external electrode 27 and the individual electrode external electrode 34A adjacent thereto.

Therefore, after depositing, for example, gold 28 on the portion to be the external electrode 27 for the diaphragm using the metal mask 37 for deposit as shown in FIG. The contact portion 26 is formed using the etching mask 36.
And the SiO ₂ film 35 of the external electrode for individual electrode 34 are removed.

As described above, by forming the Si pillar 39 between the diaphragm external electrode 27 and the individual electrode external electrode 34A adjacent thereto, the diaphragm external electrode 27 is formed with high dimensional accuracy. be able to. That is, in each of the above-described embodiments, the Si pillar 39 is provided between the diaphragm external electrode 27 and the adjacent individual electrode external electrode 34A.
Therefore, the size of the gold 28 formed on the external electrode 27 for the diaphragm with respect to the metal mask 37 for deposition was greatly expanded.

In this case, the adjacent external electrodes 3 for individual electrodes
When the gold 28 is formed on the 4A, the Si at that location cannot penetrate, and the external electrode 34A for the individual electrode cannot be used. In addition, if the expansion of the size of the gold 28 is allowed, a sufficient interval between the adjacent external electrodes for individual electrodes 34A must be ensured, and the area of the head becomes large. At this time, in order to correct the expansion of the dimension of the gold 28, it is necessary to design the mask dimension to be small in consideration of the expansion. As the mask dimension decreases, the deposition rate decreases, and it takes time to form a film. Inconvenience.

On the other hand, in the present embodiment, it is possible to form the gold 28 having the same size as the mask on the diaphragm external electrode 27 without changing the mask. Further, the etching margin in the Si dry etching using the etching metal mask 36 is also widened.

As described above, when the first substrate is etched, the portion of the contact portion where the external electrode for the diaphragm is formed and the portion between the external electrode for the individual electrode adjacent to the portion are left. The adhesiveness of the mask is improved at the time of metal film formation or etching on the diaphragm external electrode formed in the portion, and the diaphragm external electrode can be formed with good controllability.

In this case, as shown in FIGS. 13 and 14, x is the short side of the diaphragm 25, y is the short side of the contact portion 26, z is the short side of the external electrode 27 for the diaphragm, and Si is the diaphragm for the diaphragm. Assuming that the thickness of the substrate 21 is a, at least a / x> 1, a / z> 1, a / y as described in the fourth embodiment.
<Si substrate 21 for diaphragm in a configuration that satisfies <1>
Is formed, maskless etching becomes possible. In this case, gold 28 is applied to the external electrode 27 for the diaphragm.
If the Si is not dry-deposited, the diaphragm external electrode 27 remains during the Si dry etching, so that the step of depositing the gold 28 may be omitted.

Therefore, it is possible to reduce the number of masks by two, to reduce the cost and the number of steps, and to suppress the reduction in yield due to misalignment. However, due to the presence of the pillars 39 of Si, there is a possibility that it is somewhat difficult to perform pressure bonding at the time of pressure bonding of FPC or the like, but there is no possibility that pressure bonding cannot be performed, and the merit is greater.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
5 and FIG. FIG. 15 is a top view of the electrode substrate, and FIG. 16 is a cross-sectional view taken along the line GG of FIG. 15 for explaining a manufacturing process of the electrode substrate. In this embodiment, an Si substrate is used as an electrode substrate, and an N-type or P-type impurity layer is formed as an electrode. The method for manufacturing the Si substrate for the diaphragm is the same as that described in the first to fifth embodiments.

First, as shown in FIG. 16A, an SiO ₂ film 41 serving as a gap spacer is formed on the Si substrate 40 by, for example, 0.5 μm by a thermal oxide film method, and then patterned. Then, as shown in FIG. 3B, a SiO ₂ film 42 serving as a metal support formed on the contact portion 26 of the diaphragm substrate is formed by, for example, 0.2 μm by a thermal oxide film method, and then patterned by a photoresist 43. Then, the SiO ₂ film 42 where the impurity layer is to be formed is removed, and then, for example, phosphorus is implanted to form an N-type impurity layer 44 (a P-type impurity layer can also be formed).

Thereafter, as shown in FIG. 10C, the SiO ₂ film 4 serving as a protective film is also used to activate the N-type impurity layer 44.
5 is formed, for example, to have a thickness of 0.1 μm by a thermal oxidation method.
As shown in (1), a connection hole 46 is formed at a desired position of the N-type impurity layer 44. Further, as shown in FIG. 5E, a metal film is formed. However, considering that a direct bonding is performed later at a high temperature such as 800 ° C., Ti is highly heat-resistant as a metal film.
An N film 47 or the like is preferable. Subsequently, for example, plasma CVD
The SiO2 film 48 is continuously formed by the CVD method, and the SiO2 film 4 is formed.
8 and the TiN film 47 are patterned.

The PCVD-SiO ₂ film 48 formed at this time functions as an etching cover film when the contact portion 26 is etched. Since the Si substrate electrode using the impurity diffusion layer formed as described above as an electrode can form a narrow gap with high precision and has a high-quality electrode protection film,
It becomes an electrode substrate with high reliability and high yield.

However, when the impurity layer is used as an electrode, there is a problem. This will be described with reference to FIGS. FIG. 18 shows an enlarged view of the location of the connection hole 46 in a cross section taken along line HH in the top view after the final step shown in FIG.

As shown in FIG. 18A, the connection hole 4
It can be seen that the step coverage is poor in the peripheral portion of 6 due to the steps, and the TiN film 47 and the PCVD-SiO ₂ film 48 are thin. Moreover, PCVD-Si
Since the O ₂ film 48 is not a dense film like a thermal oxide film, minute pinholes are generated or the film quality of the step portion is deteriorated. As substrate cleaning before direct bonding,
In the case of cleaning with aqueous ammonia, sulfuric acid, or the like, the PCVD-SiO ₂ film 48 is slightly etched, and in some cases, the PCVD-SiO ₂ film 48 in the step portion may be completely removed. is there.

If such a portion appears in the contact portion 26 of the diaphragm substrate, the contact portion 26 may be etched not only to the TiN film 47 but also to the N-type impurity layer 44 during the Si etching. In such a state, junction leakage increases, and it becomes difficult to perform the function as an electrode.

Therefore, as shown in FIG.
An N-type impurity layer 44 is formed at a position facing the substrate, and only a sheet-shaped TiN film 47 is formed at the contact portion 26. A connection hole 46 between the N-type impurity layer 44 and the TiN film 47 is
The above-described problem can be solved by employing a configuration formed between the contact portion 26 and the contact portion 26.

As described above, a P-type or N-type impurity layer is formed on the portion of the electrode formed on the second substrate facing the diaphragm, and a heat-resistant film having high heat resistance is formed on the contact portion in a sheet shape. By adopting an electrode configuration in which a connection hole between the impurity layer and the metal film is arranged between the two, it is possible to prevent the occurrence of over-etching that reaches the Si substrate when the contact portion is etched. The reliability of the substrate is improved.

Next, another ink jet head to which the present invention is applied will be described with reference to FIGS. FIG. 19 is a cross-sectional explanatory view of the ink jet head taken along the line II of FIG. 21, and FIG.
21, FIG. 21 is a plan view of the same head, and FIG. 22 is a plan view of FIG. 21 excluding the nozzle unit.

This ink-jet head is a diaphragm / liquid chamber substrate (first substrate using a silicon substrate such as a single-crystal silicon substrate, a polycrystalline silicon substrate, or an SOI substrate). And an electrode substrate 5 which is a second substrate using a silicon substrate provided below the diaphragm / liquid chamber substrate 51.
2 and a nozzle unit 53 provided above the vibration plate / liquid chamber substrate 1.
4. A nozzle hole 57 for discharging a plurality of ink droplets, comprising a common ink chamber forming plate 55 and a nozzle plate 56, a discharge chamber 58 which is an ink flow path communicating with each nozzle hole 57, and an ink supply path to each discharge chamber 58. The common ink chamber 60, the nozzle hole 57, and the discharge chamber 5 communicating with each other through the fluid resistance portion 59 also serving as
A nozzle communication passage 61 and the like communicating with the nozzle 8 are formed.

The diaphragm / liquid chamber substrate 51 includes a discharge chamber 58 and a diaphragm (first
(Electrode) 65 is formed. The diaphragm external electrode (common electrode pad portion) 67 is provided on the same plane as the diaphragm 65. Vibrating plate / liquid chamber substrate 51
As described above, when a single crystal silicon substrate is used, a high-concentration boron layer serving as an etching stop layer is formed by injecting boron in advance to the thickness of the vibration plate, and is bonded to the electrode substrate 52. Are anisotropically etched using an etching solution such as a KOH aqueous solution. At this time, the high-concentration boron layer serves as an etching stop layer to form the diaphragm 65 and the diaphragm external electrode 67.

As described above, the diaphragm external electrode (common electrode pad portion) 67 is made of a high-concentration boron layer or the like having the same thickness as the diaphragm 65 and injected and diffused into a Si substrate. The first metal layer 6 is formed on the upper surface of the electrode 67.
8 and a second metal layer 69 is formed on the first metal layer 68.

Here, for the first metal layer 68, which is the lowermost metal layer in contact with silicon, a metal exhibiting ohmic contact with Si, for example, Al, Ti, Au or the like is used. The second metal layer 69, which is the outermost layer, is made of Si or S
Al having resistance to reactive ion etching of iO2,
Ni, Pt, Au, TiN or the like is used. This second
The metal layer 69 is made of Au or P which resists corrosion caused by halogen contained in a solvent of an organic film to be coated in mounting.
t and the like are preferable. Note that the metal layer is replaced with a two-layer structure,
One layer or three or more layers can be used.

On the other hand, an SiO ₂ film 71 serving as a gap spacer is formed on the electrode substrate 52, an electrode 73 is provided on the bottom surface of a concave portion (gap) 72 formed in the SiO ₂ film 71, and the electrode 73 is extended. External electrodes for individual electrodes (individual electrode pad portions) 74 are integrally provided, and an insulating protective film (passivation oxide film) 75 which is an electrode protective film such as an oxide film is formed on the surface of the electrode 73.

In this case, the common electrode pad portion (external electrode for diaphragm) 67 provided on the same plane as the diaphragm 65 and the individual electrode pad portion (external electrode for individual electrode) provided on the bottom surface of the gap 72 of the electrode substrate 52. 74, the steps are within 2 μm, and are arranged substantially in a line. The metal layer 68 formed on the common electrode pad portion (external electrode for diaphragm) 67,
It is preferable that the step including 69 is within 2 μm.

The passage forming plate 54 of the nozzle unit 53 has a through hole for forming an ink supply passage 59 and a nozzle communication passage 61.
Are formed in the common ink chamber forming plate 55, the through holes forming the common ink chamber 60 and the through holes forming the nozzle communication paths 61, and the nozzle plate 56 is formed with the nozzle holes 57. The surface of the nozzle plate 56 is subjected to a water-repellent treatment. Further, the nozzle unit 53 is provided with an ink supply port 76 for supplying ink to the common ink chamber 60 from outside.

As described above, by providing the diaphragm external electrode on the same plane as the diaphragm, the step between the diaphragm external electrode and the individual electrode external electrode can be reduced, and the vibration can be reduced within the small step. Since the external electrode for the plate and the external electrode for the individual electrode are arranged, the diaphragm and the electrode can be easily connected to an external circuit by connecting means including a lead wire such as an FPC. By setting the step with the external electrode within 2 μm, connection means including a lead wire such as FPC can be more easily connected,
The diaphragm and the electrodes can be easily connected to an external circuit.

Further, by arranging the external electrodes for the diaphragm and the external electrodes for the individual electrodes substantially in a line, the external electrodes for the diaphragm and the external electrodes for the individual electrodes can be connected collectively using the connection means. The connection work can be facilitated, and there is no need to use a special connection means as in the related art, so that the cost does not increase.

In this case, the diaphragm and the diaphragm external electrode are formed on the first substrate, and a metal layer is formed on the diaphragm external electrode, so that the diaphragm is formed together with the diaphragm by etching. It can be formed, or the resistance during mounting can be increased. When the metal layer of the diaphragm external electrode portion has a multilayer structure, both etching resistance and resistance during mounting can be obtained. Here, the contact resistance can be reduced by using a metal capable of making ohmic contact with silicon for a layer in contact with the first substrate in the multi-layered metal layer, and the outermost surface layer of the metal layer can be reduced. By using a metal having resistance to the halogen-based etching active species, the cost can be reduced and the etching resistance can be obtained.

Next, the manufacturing process of this ink jet head will be described with reference to FIGS. In the description, only the vicinity of the vibrating plate external electrode of adjacent chips via the external electrode portion (pad portion) is illustrated. First, FIG.
The steps up to the joining of the diaphragm / liquid chamber substrate and the electrode substrate will be described with reference to FIG. As shown in FIG. 1A, a thermal oxide film 82 serving as a gap spacer is formed on a single crystal silicon wafer 81 serving as an electrode substrate by a wet oxidation process or the like, for example, with a thickness of 2.
It is formed with a thickness of m.

Then, as shown in FIG. 13B, the organic resist film is patterned by using photolithography, and the oxide film 82 is etched with buffered hydrofluoric acid to form a concave portion 72 serving as a gap. Next, as shown in FIG. 4C, a Ti target is sputtered with Ar to which N ₂ is added to form a TiN film, an oxide film is formed on the TiN film by plasma CVD, and an organic film is formed by photolithography. After patterning the resist, the oxide film is etched and ashed. Further, etching is performed with a mixed solution of hydrogen peroxide and ammonia to form a TiN electrode 84 serving as the electrode 73 and the external electrode 74 for an individual electrode, and an oxide film 85 serving as an insulating protective film.
Cover with.

On the other hand, as shown in FIG.
Boron (B) having a high concentration of 1E20 cm ⁻³ or more is diffused into a single crystal silicon wafer 91 having a crystal plane orientation (110) serving as a liquid chamber substrate to a depth corresponding to the thickness of the diaphragm, thereby forming boron diffusion layers 92 and 93. To form It is also possible to use an SOI wafer having an active layer containing an n-type donor impurity corresponding to the thickness of the diaphragm on the diaphragm / liquid chamber substrate.

Therefore, as shown in FIG. 11E, the silicon wafer 91 is placed on the silicon wafer 81 in a vacuum, and heated to 1000.degree.
91 are directly joined.

Next, steps up to the formation of the external electrode after the direct bonding will be described with reference to FIGS.
FIG. 24 is an explanatory cross-sectional view, and FIG.
26 (a) is a cross-sectional view taken along the line LL in FIG. 26 (b), and FIG. 26 (b) is a plan view. FIG. 27A is an explanatory cross-sectional view taken along line MM of FIG. 27C, and FIG. 27B is an explanatory cross-sectional view taken along line NN of FIG. (c) is an explanatory plan view.

First, as shown in FIG. 24, a silicon wafer 91 is polished to a thickness of the vibration plate / liquid chamber substrate 51 (for example, 80 μm), a SiN film is formed by thermal CVD, and patterned by photolithography. , A SiN film mask 94 is formed.

Next, by performing anisotropic etching of Si with an aqueous KOH solution, as shown in FIG. 25, the etching rate is rapidly reduced in the high-concentration boron layer 92, and the discharge recess 66 and the high-concentration boron layer A contact portion 96 for forming the diaphragm 65 and the diaphragm external electrode 67 defined by a thickness of 92 is formed. Note that when an SOI wafer is used, silicon etching proceeds, and the etching stops at the oxide film, whereby a diaphragm and a contact portion can be formed.

Then, a multi-layered metal layer is formed on a portion of the contact portion 96 which will become the diaphragm external electrode 67 using a multi-target sputtering apparatus or a multi-evaporation source evaporation apparatus. That is, as shown in FIG. 26, a metal mask 98 is arranged on a silicon wafer 91 so as to have an opening 98 a corresponding to a diaphragm external electrode of an adjacent chip, and a first metal layer 68 is formed. This first metal layer 68
Is in contact with the high-concentration boron layer 92 of the silicon wafer 91, so that a metal exhibiting ohmic contact, for example, Al, Ti, Au or the like as described above is used.

Then, a second metal layer 69 is formed on the first metal layer 68. As the second metal layer 69, as described above, Al, Ni, Pt, Au, TiN, etc., which are resistant to reactive ion etching of Si or SiO ₂ , are preferably contained in the solvent of the organic film to be coated by mounting. Au, Pt, and the like that resist corrosion by halogen.

By thus forming the metal layer in a multilayer structure, it is possible to reduce the amount of precious metal used, which is about 50 to 100 times more expensive than ordinary metals, and to make ohmic contact with silicon. be able to. For example,
Although Ni has excellent resistance, it does not have ohmic properties with silicon. Therefore, by interposing a metal with good ohmic properties between silicon and silicon, the outermost surface layer can be formed of an inexpensive metal.

Then, by removing the metal mask 98, the first and second metal layers 101, 10 are formed on the portion of the contact portion 96 where the diaphragm external electrode is to be formed as shown in FIG.
2, a member is obtained in which the region corresponding to the individual electrode external electrode 74 is covered with the contact portion 96.

Next, steps from division into head chips to formation of external electrodes for individual electrodes will be described with reference to FIGS.
0 will be described. 28A is a cross-sectional explanatory view taken along line OO of FIG. 28B, FIG. 28B is a plan explanatory view, and FIG. 29A is a PP line of FIG. (B) is a plan view, FIG. 30 (a) is a cross sectional view taken along line QQ of FIG. 30 (c), and FIG. 30 (b) is a view of FIG. FIG. 3C is a cross-sectional explanatory view taken along the line RR, and FIG.

First, the silicon wafers 81 and 91 described above are used.
As shown in FIG. 28, the silicon wafers 81 and 91 are divided into individual head chips by performing dicing on the member bonded to the silicon wafer 91 and the vibration plate / liquid chamber substrate 51 formed from the silicon wafer 91 and the silicon wafer. A head chip is obtained in which the electrode chip 52 and the electrode substrate 52 are joined.

At this time, the diaphragm / liquid chamber substrate 51 is subjected to the above-described steps to form the diaphragm 65, the concave portion 66, the contact portion 96, and the diaphragm external electrode (common electrode pad portion) of the contact portion 96. The first and second metal layers 6
8, 69 are formed. On the other hand, an electrode 73 and an external electrode for individual electrode (individual electrode pad portion) 7
4 and the like are formed. The external electrodes for individual electrodes (individual electrode pad portions) 74 of the electrode substrate 52 are covered with the contact portions 96 of the diaphragm / liquid chamber substrate 51.

By forming a silicon wafer and dividing it into a plurality of head chips as described above, the cost can be reduced. When dicing is used to form chips, a liquid such as water is generally used to cool the blade. Dicing is performed in the area of the contact portion 96 in the area corresponding to the external electrode 74 for individual electrodes. Since the cooling water may enter the gap 72 of the device and stick to the vibration plate 65 and the individual electrode 73, the external electrode 74 for the individual electrode of the contact portion 96 may be formed. Before opening the corresponding area, dicing is performed to divide each head chip.

Thereafter, as shown in FIG. 29, it is mounted on an etching jig (etching mask) 105. As the etching mask 105, RI such as quartz or alumina is used.
A substance which does not generate a reaction product when etched during E is used. Then, RIE of silicon is performed, for example, by SF ₆
Is etched with a halogen-based gas such as a mixed gas of the above to open at least a region of the contact portion 96 corresponding to the external electrode 74 for an individual electrode. Is etched with a mixed gas of CH ₃ to form an external electrode for an individual electrode (TiN).
The films 84) 74 are exposed, and an insulating protective film 75 made of an oxide film 85 is left on the electrode 73.

As described above, the reliability of the electrical connection between the individual electrode external electrode 74 and the connection means can be improved by using an etching mask made of a material that does not generate a product in the etching process. .

When the material of the mask and the deposition of the reaction product were confirmed, the results shown in Table 1 were obtained. As shown in the same table, no deposition was observed even when stainless steel was lined with a fluorine resin.

[0127]

[Table 1]

By removing the oxide film as described above, a head chip as shown in FIG. 30 was obtained. Therefore, as described above, the nozzle unit 53 on the vibration plate / liquid chamber substrate 51 is bonded and bonded with an epoxy-based adhesive.
Is connected to the surface of the second metal layer 69 of the external electrode 67 for diaphragm and the surface of the external electrode 74 for individual electrodes via an anisotropic conductive film. At this time, since the outer n-part electrode 67 for the diaphragm and the outer electrode 74 for the individual electrode are arranged substantially in a line and have a small step, they can be collectively crimped without using a special branched FPC.

In each of the above embodiments, the description has been made of the example of the ink jet head in which the diaphragm and the electrode face in parallel. However, the diaphragm and the electrode face in a non-parallel state, that is, the gap has a cross section. The present invention can be similarly applied to an ink jet head having a shape in which the side on the diaphragm side and the side on the electrode side are non-parallel, for example, a shape in which the gap increases linearly or a curved surface shape.

[0130]

As described above, according to the ink jet head of the first aspect, since the external electrode for the diaphragm is provided on the same plane as the diaphragm, it can be easily connected to an external circuit without using a special FPC. Will be able to

According to the ink jet head of claim 2, in the ink jet head of claim 1, the step between the diaphragm external electrode and the individual electrode external electrode is 2 μm.
Since the configuration is within the range, it is possible to more easily connect to an external circuit.

According to the ink jet head of the third aspect, in the ink jet head of the first or second aspect, the external electrodes for the diaphragm and the external electrodes for the individual electrodes are arranged substantially in a line, so that a special FPC is used. And it can be easily connected to an external circuit.

According to the ink jet head of claim 4, in the ink jet head of any one of claims 1 to 3, the diaphragm and the external electrode for the diaphragm are formed on the first substrate, and the electrode and the external electrode for the individual electrode are formed. An electrode is formed on the second substrate, and at least a region of the first substrate including a region corresponding to the individual electrode external electrode of the second substrate is removed leaving the diaphragm external electrode. Therefore, it is possible to avoid a decrease in yield due to poor bonding or breakage of the diaphragm, and it is possible to simultaneously form the diaphragm external electrodes and expose the individual electrodes.

According to a fifth aspect of the present invention, in the ink jet head of any one of the first to third aspects, the diaphragm and the external electrode for the diaphragm are formed on the first substrate. Has a structure in which a metal layer is formed, so that etching corrosion resistance can be improved.

According to the ink jet head of the sixth aspect, in the ink jet head of the fifth aspect, since the metal layer of the external electrode portion for the diaphragm has a multilayer structure, improvement of corrosion resistance and reduction of cost are achieved. Will be able to do it.

According to the ink jet head of claim 7, in the ink jet head of claim 6, the layer of the metal layer that contacts the first substrate is made of a metal that can make ohmic contact with silicon. Therefore, the contact resistance can be reduced.

According to the ink jet head of claim 8, in the ink jet head of claim 6 or 7, the outermost surface layer of the metal layers is made of a metal having resistance to halogen-based etching active species. Ohmic contact and corrosion resistance can be easily obtained.

According to a ninth aspect of the present invention, there is provided a method of manufacturing an ink jet head according to any one of the first to eighth aspects, wherein the diaphragm and the external electrode for the diaphragm are formed. A first substrate and a second substrate for forming electrodes and external electrodes for individual electrodes.
When the diaphragm is formed on the first substrate after bonding the substrate and the electrode with a predetermined interval between the diaphragm and the electrode, at least the second substrate of the first substrate is formed. Forming a contact portion including a region corresponding to the region including the individual electrode external electrode and a portion forming the diaphragm external electrode to have the same thickness as the diaphragm; and a diaphragm external electrode of the contact portion. And a step of removing a region other than the region in which is formed, without increasing the number of steps,
An inkjet head having a diaphragm external electrode to which connection means such as an FPC can be easily connected can be obtained.

According to a tenth aspect of the present invention, in the manufacturing method of the ninth aspect, the first
The substrate is made of a single crystal silicon substrate, the second substrate is made of a glass substrate, a gap spacer of an SiO ₂ film is formed on the first substrate, or a recess is formed on the second substrate, and Since the first substrate and the second substrate are anodic-bonded in a state where a predetermined interval is formed between the electrodes, the connecting means such as FPC can be easily provided without increasing the number of steps. An inkjet head having a connectable diaphragm external electrode can be obtained.

According to the method of manufacturing an ink jet head of claim 11, in the manufacturing method of claim 9, the first
Both the first substrate and the second substrate are made of a single crystal silicon substrate, a gap spacer of an SiO ₂ film is formed on the first substrate and / or the second substrate, and a predetermined distance is provided between the diaphragm and the electrode. Is formed so that the first substrate and the second substrate are directly bonded to each other, so that a connecting means such as an FPC can be easily connected without increasing the number of steps. An inkjet head having external electrodes can be obtained, and a narrow gap with high accuracy can be formed.

According to a twelfth aspect of the present invention, in the manufacturing method of any one of the ninth to eleventh aspects, there is provided a method of removing a portion of the contact portion other than the portion for forming the diaphragm external electrode. Since a protective film having resistance to etching is formed beforehand on a portion where the diaphragm external electrode is to be formed, an etching margin is increased and good ohmic contact is possible.

According to a thirteenth aspect of the present invention, in the method of any of the ninth to eleventh aspects, there is provided a method of removing a portion of the contact portion other than the portion for forming the diaphragm external electrode. Previously, since a protective film having resistance to etching was formed in a region other than the region removed by etching of the first substrate,
Maskless etching is possible, reducing costs and shortening the process, suppressing a reduction in yield, and further facilitating the joining of liquid chambers formed on the diaphragm substrate, The performance is also improved.

According to a fourteenth aspect of the present invention, in the manufacturing method of the twelfth or thirteenth aspect, x is the short side of the opening of the diaphragm, y is the short side of the contact, and y is the short side of the contact part. When the thickness is a, at least (a
(X)> 1 and (a / y) <1 are satisfied, so that maskless etching can be performed, cost can be reduced, process can be shortened, and reduction in yield can be suppressed. In addition, it is possible to prevent contamination of the joint surface of the liquid chamber formed on the side etch and the diaphragm substrate.

According to a fifteenth aspect of the present invention, in the manufacturing method of any one of the ninth to fourteenth aspects, when the first substrate is etched, the diaphragm external electrode of the contact part is etched. Since a portion between the portion to be formed and the external electrode for the individual electrode adjacent to the portion to be formed is left, the external electrode for the diaphragm can be formed with good control.

According to a method of manufacturing an ink jet head according to claim 16, in the method of manufacturing an ink jet head of claim 15, x is the short side of the opening of the diaphragm, y is the short side of the contact, When the short side of the external electrode is z and the thickness of the first substrate is a, at least (a / x)>
1, (a / z)> 1, and (a / y) <1 are satisfied, so that maskless etching can be performed, thereby reducing costs, shortening the process, and reducing the yield. Can be suppressed.

According to a seventeenth aspect of the present invention, in the method for manufacturing an ink jet head according to the ninth aspect, a portion of the electrode formed on the second substrate facing the diaphragm is a P-type or N-type. Since an impurity layer is formed, a heat-resistant film having high heat resistance is formed in a sheet shape in a contact portion, and a connection hole between the impurity layer and the metal film is arranged between the two, so that the electrode structure is adopted. Reliability can be improved.

According to an eighteenth aspect of the present invention, there is provided a method for manufacturing an ink jet head according to any one of the first to eighth aspects, wherein the diaphragm and the external electrode for the diaphragm are formed. After joining a second substrate forming electrodes and external electrodes for individual electrodes to a silicon wafer serving as a first substrate to be formed, a diaphragm is formed when a flow path pattern including a discharge chamber is formed by etching on the first substrate. The silicon wafer is cut into individual head chips, leaving a region corresponding to the region including the external electrode for the individual electrode of the second substrate and a contact portion including a portion for forming the external electrode for the diaphragm. Of these, the region corresponding to the external electrode for individual electrode is removed, so that a highly reliable inkjet head can be obtained at low cost.

According to the method of manufacturing an ink jet head of the nineteenth aspect, in the manufacturing method of the eighteenth aspect, when the external electrode for the diaphragm is formed, the portion where the external electrode for the diaphragm is formed is compared with silicon. In this case, the metal layer having a low etching rate is formed, so that the first substrate can be prevented from being corroded when the diaphragm external electrode is formed on the first substrate.

According to the method of manufacturing an ink jet head of claim 20, in the manufacturing method of any one of claims 9 to 19, an etching mask of a material that does not generate a product in an etching process is used as an etching mask. The reliability of the connection with the means can be improved.

According to the method of manufacturing an ink jet head of claim 21, in the manufacturing method of claim 20, since the material of the etching mask is quartz, the reliability of the connection with the connection means is improved. be able to.

According to the method of manufacturing an ink jet head of claim 22, since the material of the etching mask is alumina in the method of manufacturing an ink jet head of claim 21, reliability of the connection with the connecting means is improved. Can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory view illustrating a basic configuration of an electrostatic ink jet head to which the present invention is applied.

FIG. 2 is an explanatory plan view of FIG. 1;

FIG. 3 is a top view of the diaphragm substrate for explaining the first embodiment of the present invention.

FIG. 4A is a diagram illustrating a manufacturing process of the diaphragm substrate, and FIG.
Sectional explanatory view along line A

FIG. 5 is a top view of an electrode substrate.

FIG. 6 is a BB diagram of FIG. 5 for explaining a manufacturing process of the electrode substrate.
Cross-sectional explanatory view along the line

FIG. 7 is a top view when a diaphragm is formed by joining a diaphragm substrate and an electrode substrate.

FIG. 8C is a view for explaining a manufacturing process of the bonding and forming the same.
Sectional explanatory view along the -C line

FIG. 9 is a top view when external electrodes are formed.

FIG. 10 is an explanatory sectional view taken along line DD of FIG. 9 for illustrating the manufacturing process of forming the external electrodes;

FIG. 11 is a top view illustrating a third embodiment of the present invention.

FIG. 12E illustrates a manufacturing step according to the first embodiment.
Sectional explanatory view along line -E

FIG. 13 is a top view illustrating a fifth embodiment of the present invention.

FIG. 14F is a view illustrating the manufacturing process of the same embodiment and is shown in FIG.
Sectional explanatory view along line -F

FIG. 15 is a top view illustrating a sixth embodiment of the present invention.

FIG. 16 illustrates a manufacturing process according to the same embodiment;
Sectional explanatory view along the -G line

FIG. 17 is a top view illustrating another example of the sixth embodiment of the present invention.

FIG. 18 is a sectional view H of FIG. 17 illustrating the manufacturing process of the embodiment;
Sectional explanatory view along line -H

FIG. 19 is an explanatory sectional view of another inkjet head according to the present invention, taken along line II of FIG. 21;

FIG. 20 is an explanatory cross-sectional view of the head taken along line JJ in FIG. 21;

FIG. 21 is an explanatory plan view of the head.

FIG. 22 is an explanatory plan view showing a state where the nozzle unit is removed from FIG. 21;

FIG. 23 is an explanatory view illustrating a process of bonding the diaphragm / liquid chamber substrate and the electrode substrate of the head.

FIG. 24 is a cross-sectional explanatory view illustrating a process until an external electrode is formed after the direct bonding.

25A is a cross-sectional explanatory view taken along the line KK of FIG. 25B, and FIG.

26 (a) is a cross-sectional view taken along line LL of FIG. 26 (b), and FIG. 26 (b) is a plan view.

FIG. 27A is a cross-sectional explanatory view taken along the line MM of FIG. 27C, FIG. 27B is a cross-sectional explanatory view taken along the line NN of FIG.
(C) is an explanatory plan view

FIG. 28 (a) similarly illustrates steps from division into a head chip to formation of an external electrode portion for an individual electrode (b).
(B) is a plan explanatory view along the line OO of FIG.

29A is a cross-sectional view taken along the line PP of FIG. 29B, and FIG. 29B is a plan view.

30 (a) is a sectional view taken along line QQ in FIG. 30 (c), FIG. 30 (b) is a sectional view taken along line RR in FIG. 30 (c), and FIG.

[Description of Signs] 1 ... first substrate, 2 ... cover member, 3 ... electrode substrate, 5 ... nozzle hole, 7 ... discharge chamber, 10 ... vibrating plate, 16 ... electrode, 20 ...
Diaphragm board, 21: Si substrate (first substrate), 25: diaphragm, 26: contact portion, 27: external electrode for diaphragm,
28 ... gold, 30 ... electrode substrate, 31 ... glass substrate, 32 ...
Gap, 33 ... electrode, 34 ... external electrode for individual electrode, 3
5: protective film, 39: pillar, 51: diaphragm / liquid chamber substrate, 52
... electrode substrate, 53 ... nozzle unit, 57 ... nozzle hole,
58 discharge chamber, 65 diaphragm, 67 external electrode for diaphragm, 68 first metal layer, 69 second metal layer, 73 electrode, 74 external electrode for individual electrode, 81, 91 silicon wafer .

Continued on the front page (72) Inventor Makoto Tanaka 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Eiji Mochizuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company

Claims (22)

[Claims] A nozzle hole for discharging ink droplets; a discharge chamber communicating with the nozzle hole; a diaphragm forming at least one wall surface of the discharge chamber; and an electrode disposed to face the diaphragm. In an ink jet head for discharging the ink droplets by deforming the vibration plate by an electrostatic force generated between the vibration plate and an electrode, an external electrode for the vibration plate is provided on the same plane as the vibration plate. head. 2. The ink jet head according to claim 1, wherein a step between the external electrode for the diaphragm and the external electrode for an individual electrode is within 2 μm. 3. The ink jet head according to claim 1, wherein the external electrodes for the diaphragm and the external electrodes for the individual electrodes are arranged substantially in a line. 4. The ink jet head according to claim 1, wherein the diaphragm and the external electrode for the diaphragm are formed on a first substrate, and the electrode and the external electrode for an individual electrode are formed on a second substrate. Formed on a substrate, at least a portion of the first substrate including a region corresponding to the individual electrode external electrode of the second substrate is removed leaving the diaphragm external electrode. Inkjet head. 5. The ink jet head according to claim 1, wherein the diaphragm and a diaphragm external electrode are formed on a first substrate, and a metal layer is formed on the diaphragm external electrode. An ink-jet head characterized in that: 6. The ink jet head according to claim 5, wherein the metal layer of the diaphragm external electrode has a multilayer structure. 7. The ink jet head according to claim 6, wherein a layer of the metal layer that contacts the first substrate is a metal that can make ohmic contact with silicon. 8. The ink jet head according to claim 6, wherein an outermost surface layer of said metal layer is made of a metal having resistance to halogen-based etching active species. 9. The method for manufacturing an ink jet head according to claim 1, wherein the first substrate on which the diaphragm and the external electrode for the diaphragm are formed, the electrode, and the individual electrode. After joining a second substrate forming an external electrode for use with a predetermined interval between the diaphragm and the electrode, when forming the diaphragm on the first substrate, the first substrate A contact portion including at least a region corresponding to a region including the external electrode for an individual electrode of the second substrate and a portion for forming the external electrode for the diaphragm is formed to have the same thickness as the diaphragm. And a step of removing a region of the contact portion other than a region where the diaphragm external electrode is to be formed. 10. The method for manufacturing an ink jet head according to claim 9, wherein said first substrate is made of a single crystal silicon substrate, said second substrate is made of a glass substrate, and said first substrate is made of SiO _2. A gap spacer of a film is formed or a concave portion is formed in the second substrate so that a predetermined interval is formed between the diaphragm and the electrode, and the first substrate and the second substrate are formed. A method for manufacturing an ink jet head, comprising: anodically bonding a substrate to the substrate. 11. The method for manufacturing an ink jet head according to claim 9, wherein the first substrate and the second substrate are each formed of a single crystal silicon substrate, and the first substrate and / or the second substrate are formed. Forming a gap spacer of an SiO ₂ film in a state where a predetermined gap is formed between the diaphragm and the electrode, and directly joining the first substrate and the second substrate. Manufacturing method of an inkjet head. 12. The method of manufacturing an ink jet head according to claim 9, wherein the step of removing the portion of the contact portion other than the portion on which the diaphragm external electrode is formed is performed. A method for manufacturing an ink jet head, comprising: forming a protective film having resistance to etching on a portion where a plate external electrode is to be formed. 13. The method for manufacturing an ink jet head according to claim 9, wherein the step of removing a portion of the contact portion other than a portion on which the external electrode for a diaphragm is formed is performed. A method for manufacturing an ink jet head, comprising: forming a protective film having resistance to etching in a region other than a region removed by etching of one substrate. 14. The method for manufacturing an ink jet head according to claim 12, wherein the short side of the opening of the diaphragm is x, the short side of the contact is y, and the thickness of the first substrate is a. At least (a / x)> 1,
(A / y) <1. A method for manufacturing an ink jet head, characterized by satisfying a relationship of <1. 15. The method for manufacturing an ink jet head according to claim 9, wherein a portion of the contact portion on which the diaphragm external electrode is formed when the first substrate is etched. A method for manufacturing an ink jet head, wherein a portion between the external electrode for an individual electrode and an adjacent external electrode is left. 16. The method for manufacturing an ink jet head according to claim 15, wherein x is a short side of the opening of the diaphragm, y is a short side of the contact portion, and z is a short side of the external electrode for the diaphragm. When the thickness of the first substrate is a, at least (a / x)> 1, (a / z)> 1, (a / y)
<1. A method for manufacturing an ink-jet head, wherein the method satisfies the relation (1). 17. The method for manufacturing an inkjet head according to claim 9, wherein a P-type or N-type impurity layer is formed on a portion of the electrode formed on the second substrate facing the diaphragm. A method for manufacturing an ink jet head, wherein a heat-resistant film having high heat resistance is formed in a contact portion in a sheet shape, and an electrode configuration is provided in which a connection hole between an impurity layer and a metal film is arranged between the two. 18. The method for manufacturing an ink-jet head according to claim 1, wherein a silicon wafer serving as a first substrate on which the vibration plate and the external electrode for the vibration plate are formed is provided. After joining a second substrate on which electrodes and external electrodes for individual electrodes are formed, when forming a flow path pattern including the discharge chamber by etching on the first substrate, the vibration plate and the second substrate are bonded together. After cutting the silicon wafer into individual head chips, leaving a region corresponding to the region including the individual electrode external electrode and a contact portion including a portion forming the diaphragm external electrode, A method for manufacturing an ink jet head, wherein a region corresponding to the external electrode for an individual electrode is removed. 19. The method for manufacturing an ink jet head according to claim 18, wherein, when forming the diaphragm external electrode, an etching rate is lower in a portion where the diaphragm external electrode is formed than in silicon. A method for manufacturing an ink jet head, comprising forming a metal layer. 20. The method for manufacturing an ink jet head according to claim 9, wherein an etching mask of a material that does not generate a product in an etching process is used as the etching mask. Method. 21. The method for manufacturing an ink jet head according to claim 20, wherein a material of said etching mask is quartz. 22. The method for manufacturing an ink jet head according to claim 21, wherein a material of said etching mask is alumina.