JP2002264332A - Electrostatic actuator, its manufacturing method, ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the member in an ink jet recording head touching ink liquid against corrosion. SOLUTION: The ink jet recording head has a corrosion resistant thin film 125a exhibiting excellent corrosion resistance against liquid drop formed on the surface of a liquid chamber substrate 111, the surface (upper surface) of a silicon diaphragm 112, the inner wall of a driving liquid chamber 118, the inner wall of a common liquid chamber 116, and the inner wall of a liquid channel 117. Furthermore, a corrosion resistant thin film 125b is formed on the inner wall of a liquid supply opening 115 and a through opening 105 for supplying liquid from the rear side. Since the inner wall of the driving liquid chamber 118, the inner wall of the common liquid chamber 116, the inner wall of the liquid channel 117 touching the liquid drop, and the diaphragm 112 are protected completely against corrosion with the liquid drop (ink), quality of the liquid drop can be prevented from deteriorating due to a substance, e.g. ions, eluted from a member into the liquid drop (ink), and the part touching the liquid is protected against corrosion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a diaphragm is deformed by electrostatic attraction, a liquid is introduced from the back surface of a support using a repulsive force of the deformed diaphragm, and a droplet is discharged from a nozzle hole. The present invention relates to a structured electrostatic actuator, a method of manufacturing the same, an inkjet recording head, and an inkjet recording apparatus.

[0002]

2. Description of the Related Art For example, an ink jet head used in an on-demand type ink jet printer is disclosed in International Publication No. WO98 / 42513. In the ink jet head described in this publication, an ink-resistant thin film having corrosion resistance to ink is formed on the surface of a diaphragm constituting a pressure chamber for applying pressure to and discharging ink. . Among these, Ti, Ti are used as ink-resistant thin films having corrosion resistance.
Examples using compounds and Al2O3 are described.

Further, Japanese Patent Application Laid-Open No. 10-291322 discloses that a silicon oxide film is formed on the surface of a diaphragm constituting a pressure chamber and then laminated to form oxides, nitrides and the like having ink resistance. An example in which a thin film of metal or the like is formed is disclosed.

[0004]

Incidentally, Ti, Ti compounds, Al2O3, and JP-A-10-29 as disclosed in the above-mentioned International Publication No. WO 98/42513.
When an ink-resistant thin film having the corrosion resistance of a silicon oxide film as disclosed in Japanese Patent No. 1322 is formed only on the diaphragm of an ink jet head, it is effective for preventing corrosion of the diaphragm, but the ink is in contact with the diaphragm. Since corrosion to members other than the diaphragm is not considered at all, substances such as ions eluted from this member into the ink deteriorate the quality of the ink, and when used as an ink recording head, the image quality deteriorates. There was a possibility that the above-mentioned problem might occur.

Further, when the corrosion-resistant thin film is formed as a single layer as in the above-mentioned conventional example, droplets seep out from pinholes generated in the corrosion-resistant thin film due to minute particles mixed in the formation process and vibrate. The plate was corroded and there was a problem in reliability.

Further, the diaphragm buckles and bends due to the internal stress of the corrosion-resistant thin film, and the flexure of the diaphragm causes variations in the jetting characteristics between droplets during droplet ejection,
There is a possibility that the cause of the droplet discharge failure may be caused.

In addition, Ti, which has corrosion resistance to ink,
When an ink-jet head having a Ti compound thin film formed on a diaphragm of an ink-jet head is used, a great difference occurs in ink corrosion resistance depending on the composition, and furthermore, as disclosed in JP-A-10-291322. In the conventional example in which a silicon oxide film and an ink-resistant thin film are sequentially laminated, there is a problem that the silicon oxide film does not have corrosion resistance to all kinds of inks and lacks reliability.

Accordingly, an object of the present invention is to provide an electrostatic actuator, a method of manufacturing the same, an ink jet recording head and an ink jet recording apparatus which have solved the above-mentioned problems.

[0009]

The present invention has the following features to solve the above-mentioned problems.

According to the first aspect of the present invention, a thin film having corrosion resistance to the droplet is formed on the liquid flow path in contact with the droplet and the diaphragm. The constituent members and the liquid droplets are completely shut off, and the liquid passages in contact with the liquid droplets and the members constituting the diaphragm are not corroded by the liquid droplets at all, and eluted from the member into the liquid droplets. It is possible to prevent substances such as ions from deteriorating the quality of the droplet. Therefore, when used as an ink recording head, deterioration of image quality can be prevented.

According to the second aspect of the present invention, since the corrosion-resistant thin film is formed on the entire back surface of the support, the adhesive strength to an external support such as a frame is improved, and the yield of the assembly process is improved. I do.

According to the third aspect of the present invention, since a thin film having corrosion resistance is formed on the inner wall of the liquid chamber formed between the diaphragm and the nozzle hole, the member constituting the side wall of the liquid chamber is formed. The degradation of droplets due to the elution of substances from
The bonding strength with a nozzle plate having a nozzle hole for ejecting a droplet is improved, and the yield of assembly is improved.

According to a fourth aspect of the present invention, there is provided a liquid passage of an electrostatic actuator and a first diaphragm having corrosion resistance.
And the second thin film having corrosion resistance on the back surface of the support are formed in separate steps, so that various film qualities and thicknesses can be changed according to the process. spread.

According to the fifth aspect of the invention, since a thin film having corrosion resistance is formed on the diaphragm of the electrostatic actuator, the inner wall of the ink liquid chamber, and the back surface of the support, any type of ink can be used. A compatible inkjet recording head can be realized. Further, since it is an electrostatic type, an ink jet recording head excellent in low power consumption can be realized.

The invention according to claim 6 is an ink jet recording apparatus using an ink jet recording head in which a thin film having corrosion resistance is formed on the diaphragm, the inner wall of the ink liquid chamber, and the back surface of the support. Therefore, high-quality images can be recorded with low power consumption.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a first embodiment of an electrostatic actuator according to the present invention, and FIGS. 2 to 5 are AA 'section, BB' section, and CC 'section in FIG. 1, respectively. , DD ′ is a longitudinal sectional view showing a section.

As shown in FIG. 1 to FIG.
The electrostatic actuator includes a silicon diaphragm 112, a driving liquid chamber 118 in which droplets are pressurized, a common liquid chamber 116, and a liquid flow path 1.
17 is a plane orientation (11) formed by anisotropic etching.
0) single crystal silicon substrate 111 and droplet nozzle hole 11
A cover plate 114 such as a glass plate, a metal plate, or a silicon plate on which a liquid 9 is formed, and a liquid supply port 1 for supplying a liquid from the back side.
An electrode substrate (101, 10) made of a single crystal silicon substrate having a plane orientation (100) or (110) on which
2, 104, 121).

Single crystal silicon substrate 111 as a liquid chamber substrate
The silicon diaphragm 11 driven by electrostatic attraction corresponds to the driving liquid chamber 118 and the individual droplet nozzle holes 119.
2 are formed. Further, a liquid supply port 115 for supplying a liquid from the back surface side is formed on the back surface of the single crystal silicon substrate (support) 101. This liquid supply port 115
Is connected to the internal common liquid chamber 116 through the through-hole 105 penetrating from the back surface to the front surface. Further, the driving liquid chamber 118 and the common liquid chamber 116 communicate with each other via a liquid channel 117.

The surface of the liquid chamber substrate 111, the surface (upper surface) of the silicon diaphragm 112, the inner wall of the driving liquid chamber 118, the inner wall of the common liquid chamber 116, and the inner wall of the liquid flow path 117 A corrosion-resistant thin film 125a having excellent corrosion resistance is formed. Further, a corrosion-resistant thin film 125b having corrosion resistance is also formed on the inner wall of the liquid supply port 115 for supplying the liquid from the back side and the through-hole 105. Therefore, the inner wall of the driving liquid chamber 118, the inner wall of the common liquid chamber 116, the inner wall of the liquid flow path 117 where the liquid droplets are in contact, and the diaphragm 112 are not corroded by the liquid droplets (ink) at all. Substances such as ions eluted into the droplet (ink) can be prevented from deteriorating the quality of the droplet, and corrosion of the liquid contact portion can be prevented.

These corrosion resistant thin films 125a and 125b
Is a thin film having an internal stress formed by a sputtering method, a CVD method, an oxidation method or the like and having a tensile stress of 10 to 2,000, preferably 100 to 1,000, in thickness.
Even if the corrosion resistant film 125a is formed on the surface of the diaphragm 112, the diaphragm 112 does not bend. Further, the corrosion-resistant thin films 125a and 125b are a single layer or a titanium nitride containing at least 1% or more of oxygen atoms in a laminated film sequentially laminated in order to prevent pinholes having minute holes.

Further, the silicon diaphragm 112 forming the driving liquid chamber 118 corresponding to each droplet nozzle hole 119 is provided.
Are arranged opposite to the drive electrodes 121 for applying a voltage for driving the electrostatic actuator using the silicon oxide 102 as a gap spacer. The discharge direction of the droplet is a direction indicated by an arrow 120 determined by the arrangement direction of the droplet nozzle holes 119.

In the first embodiment, the silicon substrate 101
Is a plane orientation (100), and a low efficiency p of 10 to 30 Ω-cm.
It consists of a single crystal silicon substrate. The drive electrode 121 is formed of a silicon oxide 1 having a thickness of 2 μm on the single crystal silicon substrate 101.
02 arranged in a concave portion having a depth of 0.4 μm,
Titanium nitride sequentially formed on an oxide film by a reactive sputtering method, which is insulated from each other.

The silicon oxide 102 is formed by a thermal oxidation method. Further, an insulating film 104 made of a silicon oxide film having a thickness of 150 nm formed by a plasma CVD method is formed on the titanium nitride of the drive electrode. The insulating film 104 made of the silicon oxide film is for securing insulation between the diaphragm 112 and the drive electrode 121.

Reference numeral 108 denotes a pad region for applying a drive voltage to the drive electrode 121 of the electrostatic actuator from which the insulating film 104 has been removed by etching. Plane orientation (11
2) A 2 μm-thick diaphragm 112 containing boron impurity atoms of 1E19 / cm 3 or more formed by anisotropically etching the single crystal silicon substrate 111 of KOH with a driving electrode 121 through a silicon oxide film 102 serving as a gap spacer. Are arranged to face each other.

Surface orientation (110) single crystal silicon substrate 11
In 1, a driving liquid chamber 118 formed by anisotropic etching of KOH and a common liquid chamber 416 for supplying a liquid to the driving liquid chamber 118 are formed. on the other hand,
The through-hole 10 penetrating from the back surface to the front surface is provided on the single crystal silicon substrate 101 having the plane orientation (100) on which the drive electrode is formed.
A liquid supply port 115 for supplying a liquid from the back side to the common liquid chamber 116 through 5 is formed, and the driving liquid chamber 118 and the common liquid chamber 116 are communicated by the liquid flow channel 117 as described above. .

In the first embodiment, as described above, the liquid chamber substrate 11
1, the surface of the silicon diaphragm 112, the driving liquid chamber 11
8, the inner wall of the common liquid chamber 116, the inner wall of the liquid flow path 117, the inner wall of the liquid supply port 115, and the inner wall of the through flow path 105,
Corrosion-resistant thin films 125a and 125b, each made of titanium nitride having an internal stress of tensile stress, have a thickness of 1 by sputtering.
It is formed with a thickness of 000 mm. This corrosion-resistant thin film 1
25a and 125b contain about 10% of oxygen atoms.

At this time, the diaphragm 112 is not bent at all by buckling. Further, a metal plate 114 having a droplet nozzle hole 119 formed thereon is adhered on the liquid chamber. In such an electrostatic actuator, the diaphragm 1
12 was electrically grounded, and a drive voltage was applied to the drive electrode 121 via the electrode pad 108 to drive the drive electrode 121 at a constant frequency. When a voltage is applied, 1 between the diaphragm 112 and the drive electrode
Electrostatic attraction acts on 21 and the diaphragm 112 does not bend due to buckling of the corrosion-resistant thin film 125a made of titanium nitride, and is therefore sufficiently attracted to the drive electrode side by electrostatic attraction.

As a result, the driving liquid chamber 118 has a sufficiently negative pressure, and the liquid connected to the liquid supply port 115 flows through the through flow path 10.
5, the common liquid chamber 116 and the driving liquid chamber 11 through the flow path 117.
Liquid is supplied to 8. Therefore, the diaphragm 112 returns to the original position due to the rigidity of the silicon in accordance with the frequency of the driving voltage, and at this time, the driving liquid chamber 118 is pressurized. Therefore, the liquid in the driving liquid chamber 118 is stably discharged from the droplet nozzle holes 119 in the direction of 120.

Further, as a result of measuring the variation of the injection characteristics between bits in this state, it was possible to obtain the injection characteristics with very good uniformity. In addition, as a result of a reliability test using droplets, it was found that silicon, which is a constituent member of the electrostatic actuator of the present invention, was not eluted in the droplets, and that it had sufficient corrosion resistance.

Next, the configuration of the second embodiment will be described with reference to FIGS. FIG. 6 is a plan view of the electrostatic actuator according to the second embodiment, and FIGS.
AA 'section, BB' section, CC 'section, D-
It is a longitudinal cross-sectional view which shows the D 'cross section.

As shown in FIGS. 6 to 10, in the electrostatic actuator of the second embodiment, a silicon vibration plate 212, a driving liquid chamber 218 to which liquid droplets are pressurized, a common liquid chamber 216, and a liquid flow path 217 are formed. A liquid is supplied from the back side of a single-crystal silicon substrate 211 having a plane orientation (110) formed by anisotropic etching, a cover plate 214 such as a glass plate, a metal plate, or a silicon plate provided with droplet nozzle holes 219. Orientation (100) or (110) in which the liquid supply port 215 is formed.
Electrode substrates 201 and 20 made of a single crystal silicon substrate
2, 204, and 221.

Single crystal silicon substrate 2 as a liquid chamber substrate
11, a silicon diaphragm 2 driven by electrostatic attraction corresponding to the driving liquid chamber 218 and the individual droplet nozzle holes 219;
12 are formed. Further, a liquid supply port 215 for supplying a liquid from the back surface side to the common liquid chamber 216 through a through-hole 205 penetrating the electrode substrate from the back surface to the front surface is formed, and the driving liquid chamber 218 and the common liquid chamber 216 are formed of a liquid. Channel 217
Is communicated by

The surface of the liquid chamber substrate 211 and the silicon diaphragm 2
12, the surface of the driving liquid chamber 218, the surface of the common liquid chamber 216, and the surface of the liquid flow path 217 have a corrosion-resistant thin film 225 against droplets.
a is formed. Further, a corrosion-resistant thin film 225b is formed not only on the liquid supply port 215 and the through-hole 205 for supplying a liquid from the back side, but also on the entire back surface of the single crystal silicon substrate 201 as a support.

The corrosion-resistant thin film 225b not only prevents the actuator from being corroded by droplets but also improves the adhesive strength when the electrostatic actuator is assembled and assembled on a frame (not shown). Reliability is improved. These corrosion resistant thin films 225
a and 225b indicate that the internal stress formed by a sputtering method, a CVD method, an oxidation method, or the like has a tensile stress of 10 ° to 2 mm.
It is a thin film of 000 °, preferably 100 ° to 1000 °. Even if the corrosion resistant film 225a is formed on the diaphragm 212, the diaphragm 212 does not bend.

The corrosion-resistant thin films 225a, 225
b is a single layer or titanium nitride containing preferably at least 1% or more of oxygen atoms in a laminated film sequentially laminated to prevent micro holes (pinholes). Further, the silicon diaphragm 212 forming the driving liquid chamber 218 corresponding to each of the droplet nozzle holes 219 includes a driving electrode 221 for applying a voltage for driving an electrostatic actuator using the silicon oxide 202 as a gap spacer. Are arranged opposite to each other. The droplet discharge direction is a direction indicated by an arrow 220 determined by the arrangement direction of the droplet nozzle holes 119.

The outline of the overall structure of the electrostatic actuator of the present invention has been described above.
1, 201 will be described.

In FIG. 1 to FIG.
Reference numeral 1 denotes an n-type or p-type single crystal silicon substrate. Normally, a single-crystal silicon substrate with a plane orientation of 100 is used, but there is no problem even if a single-crystal silicon substrate with a plane orientation of (110) is used depending on the process. Alternatively, a glass substrate may be used instead of the silicon substrate.

Reference numerals 121 and 221 denote single crystal silicon substrates 1
A drive electrode for applying a voltage for driving the silicon diaphragms 112 and 212 formed in the recesses of the silicon oxides 102 and 202 on the first and second electrodes 201 and 201, whichever may be a conductor.

The drive electrodes 121 and 221 are insulated and separated from each other, and are preferably formed by a reactive sputtering method, a CVD method or the like, preferably a refractory metal such as titanium, tungsten, tantalum or the like, and a nitride thereof, or a nitride thereof. A compound or a stacked structure thereof, preferably titanium nitride or a stacked structure of titanium and titanium nitride sequentially formed on the silicon oxide films 102 and 202, formed by thermally oxidizing the single crystal silicon substrates 101 and 201 Gap spacer 1 of the formed silicon oxide films 102 and 202
03,203.

The gap spacers 103, 203
This is for forming a gap between the silicon diaphragms 112 and 212 and the drive electrode 121, and the silicon diaphragm 11 is formed through the gap spacers 103 and 203.
The electrostatic attraction is generated by applying a voltage to the drive electrodes 121 and 221 facing the first and second electrodes 212 and 221.

Reference numerals 108 and 208 denote drive electrodes 121 and 221.
This is a driving voltage application pad portion that conducts to the electrode substrate, and is a pad portion for applying a voltage from the outside to the electrode substrate and further performing mounting such as FPC and wire bonding.

The structure of the second embodiment shows a case where the corrosion-resistant thin film is a single-layer titanium nitride, and is formed on the diaphragm, inside and inside the driving liquid chamber, between the common liquid chamber and the liquid flow path, and further, between the frame and the static liquid. Single-crystal silicon substrate 201 as a support for improving the adhesive strength when assembling the electric actuator
An example in which a corrosion-resistant thin film is formed on the entire back surface including the liquid supply port 215 of FIG.

The electrostatic actuator of the second embodiment is manufactured according to the procedure (process flow) shown in FIGS. The silicon substrate 201 has a plane orientation (10
0), a p-single-crystal silicon substrate having a resistivity of 10 to 30 Ω-cm. The drive electrode 221 is a single crystal silicon substrate 201
Titanium nitride formed on a silicon oxide 202 having a thickness of 2 μm and having a depth of 0.6 μm and formed on an oxide film by a reactive sputtering method and is insulated from each other.

The silicon oxide 202 is formed by a thermal oxidation method. Further, a 200 nm-thick silicon oxide film 204 formed by a plasma CVD method is formed on the titanium nitride of the drive electrode. This silicon oxide film 204
Is for ensuring insulation between the diaphragm 212 and the drive electrode 221.

Reference numeral 208 denotes a drive electrode 221 of the electrostatic actuator from which the silicon oxide film 204 has been removed by etching.
This is a pad area for applying a drive voltage to the pad. Boron impurity atoms formed by anisotropically etching a single crystal silicon substrate 211 having a plane orientation of (110) with KOH are
The diaphragm 212 having a thickness of 2 μm and a driving electrode 22 through the silicon oxide film 202 serving as a gap spacer is formed.
1 are arranged.

Plane orientation (110) single crystal silicon substrate 21
In 1, a driving liquid chamber 218 formed by KOH anisotropic etching and a common liquid chamber 216 for supplying a liquid to the driving liquid chamber 218 are formed. on the other hand,
The through-hole 20 penetrating from the back surface to the front surface is provided on the single crystal silicon substrate 201 having the plane orientation (100) on which the drive electrode is formed.
A liquid supply port 215 for supplying a liquid from the back side to the common liquid chamber 216 through the second liquid chamber 216 is formed, and the driving liquid chamber 218 and the common liquid chamber 216 are communicated by the liquid flow path 217 as described above. .

On the other hand, the surface of the liquid chamber substrate 211, the surface of the silicon diaphragm 212, the driving liquid chamber interior 218, and the common liquid chamber interior 21
6. The entire surface of the single crystal silicon substrate 201 including the liquid flow path 217, the through flow path surface 205, and the liquid supply port 215 for supplying the liquid from the back side is made of titanium nitride having an internal stress of tensile stress. Corrosion resistant thin film 225a, 2
25b is formed to a thickness of 1000 ° by a sputtering method.

The titanium nitride of the corrosion-resistant thin films 225a and 225b contains about 5% of oxygen atoms. At this time, the diaphragm 212 is not bent at all by buckling. Further, the metal plate 2 on which the droplet nozzle holes 219 are formed.
14 is attached on the liquid chamber.

In the thus configured electrostatic actuator of the second embodiment, the diaphragm 212 is electrically grounded,
Further, a drive voltage is applied to the drive electrode 221 via the electrode pad 208 to drive at a constant frequency. When a voltage is applied, an electrostatic attraction acts between the diaphragm 212 and the drive electrode 221. Therefore, the diaphragm 212 is sufficiently pulled toward the drive electrode 221 by electrostatic attraction, since the diaphragm 212 does not bend due to buckling of the corrosion-resistant thin film 225a made of titanium nitride.

As a result, the inside of the driving liquid chamber 218 has a sufficient negative pressure. Therefore, the liquid connected to the liquid supply port 215 passes through the through channel 205, the common liquid chamber 216, and the channel 217.
And is supplied to the driving liquid chamber 218.

Further, the diaphragm 212 returns to the original position due to the rigidity of the silicon in accordance with the frequency of the driving voltage,
At this time, the driving liquid chamber 218 is pressurized. Therefore, the liquid in the driving liquid chamber 218 flows through the droplet nozzle hole 219 and the arrow 22.
Discharge is stably performed in the direction of 0.

Further, as a result of measuring the variation between the bits of the injection characteristics in this state, it was possible to obtain the injection characteristics with very good uniformity. In addition, as a result of a reliability test using droplets, it was confirmed that silicon, which is a constituent member of Example 2, was not eluted in the droplets, and that corrosion resistance was sufficient.

Further, since the corrosion-resistant thin film 225b made of titanium nitride is formed over the entire back surface of the single crystal silicon substrate 201, the adhesive strength when assembled with a frame (not shown) is increased, and the reliability is improved. The performance is further improved than in the case of Example 1.

Next, a procedure for manufacturing the electrostatic actuator of the second embodiment will be described. Note that, in the case of the first embodiment described above, it is created by the same process (creation procedure) as in the second embodiment. 11 to 19 are process diagrams showing steps 1 to 9 for manufacturing the electrostatic actuator according to the second embodiment. FIGS. 11A to 19A are cross-sectional views taken along the line AA ′ of FIG. 11 (b) to FIG. 19 (b) correspond to A- in FIG. 11 (a) to FIG.
FIG. 4 is a cross-sectional view of a drive electrode portion indicated by A ′.

In the manufacturing procedure 1, as shown in FIG. 11ab, first, the plane orientation (100) or (111),
(110) p-type or n-type single-crystal silicon substrate 301
A silicon oxide film 302 is formed thereon by a thermal oxidation method.

In the next manufacturing procedure 2, FIGS. 12A and 12B
As shown in (2), patterning for defining the drive electrode region and the substrate electrode region is performed on the silicon oxide by ordinary photolithography and etching. The etching is performed by a dry etching method or a wet etching method.

In the next manufacturing procedure 3, FIGS. 13 (a) and 13 (b)
As shown in above, a high melting point metal such as titanium, tungsten, tantalum and the like, a nitride thereof, a compound thereof, or a laminated structure thereof formed on a patterned silicon oxide film by a reactive sputtering method, a CVD method, or the like. Preferably, titanium nitride is sequentially formed on the entire surface of the silicon oxide film 302.

In the next manufacturing procedure 4, FIGS. 14A and 14B
As shown in FIG. 5, an insulator formed on the refractory metal 321 by a CVD method, a sputtering method, an evaporation method, or the like, desirably, silicon oxide is formed, and patterning for defining the drive electrode 321 is performed on the insulator 304. Then, the refractory metal 321 is etched and patterned using the insulator 304 as an etching mask. At this point, the electrode substrate in which the drive electrode 321 having the insulator 304 on the high melting point metal is arranged in the concave portion 302a formed in the silicon oxide film 302 is completed.

In the next manufacturing procedure 5, FIGS. 15A and 15B
As shown in the figure, the conduction type is P-type or N-type, and the plane orientation (1
10) A single crystal silicon substrate 311 having a diffusion region 312 formed by diffusing impurities exhibiting P-type or N-type conductivity of 1E19 / cm3 or more to a depth equal to the thickness of the diaphragm on one side of the single-crystal silicon substrate 311; The electrode substrate 321 is aligned and joined, and an etching mask pattern 313a defining a driving liquid chamber 318 and a common liquid chamber 316 is formed on the single crystal silicon substrate 311.
On the surface of No. 01, an etching mask pattern 313b for defining the liquid supply port 315 is formed. At this time, a material having selectivity to silicon, such as silicon oxide, silicon nitride, or tantalum pentoxide, is selected for the etching mask 313b.

Next, a single-crystal thin-film silicon film having a thickness equal to the diaphragm thickness is formed on a single-crystal silicon substrate having a plane orientation of (110) via a silicon oxide film: an SOI (silicon on insulator) substrate; The electrode substrates may be joined. In addition, the electrode substrate and the liquid chamber substrate are bonded by a direct bonding method in which the bonding is performed at a temperature of about 500 ° C. and then a heat treatment at 800 ° C. or more. When a glass substrate is used, anodic bonding is performed.

In the next manufacturing procedure 6, FIGS. 16 (a) and 16 (b)
Next, as shown in FIG. 3, the substrate in which the electrode substrate and the liquid chamber substrate are joined together is
Anisotropic etching is performed simultaneously with KOH, TMAH, etc. from the electrode side where the electrodes 13a and 313b are formed and from the liquid chamber substrate side to form a through-hole penetrating the driving liquid chamber, the common liquid chamber, and the front and back surfaces. Further, the etching is spontaneously stopped in the diffusion region 312 containing the impurity at a high concentration, and the vibration plate 312 is formed. Note that when anisotropic etching is performed using an SOI substrate, the etching stops on the silicon oxide film. In this case, there is no problem even if the silicon oxide film is removed.

In the next manufacturing procedure 7, FIGS. 17 (a) and 17 (b)
As shown in FIG. 7, the surface of the liquid chamber substrate 311 and the surface of the silicon diaphragm 312 are next provided with a corrosion-resistant thin film
a is formed. The corrosion-resistant thin film 325a is a single layer formed by a sputtering method, a CVD method, or the like, or a laminated film containing at least oxygen atoms,
This is titanium nitride containing oxygen atoms in an amount of at least%. Here, the corrosion-resistant thin film 325a is not limited to titanium nitride, but may be any thin film having corrosion resistance to droplets.

In the next manufacturing procedure 8, FIGS. 18A and 18B
As shown in (2), a corrosion-resistant thin film 325b for droplets is also formed on the entire surface of the substrate 301 on which the electrodes are formed. At this time, a corrosion resistant film 325b is also formed inside the through hole. The corrosion-resistant thin film 325b is a single layer formed by a sputtering method, a CVD method, or the like, or a laminated film containing at least oxygen atoms, desirably 1.0.
This is titanium nitride containing oxygen atoms in an amount of at least%.

Here, the corrosion-resistant thin film 325b is not limited to titanium nitride, but may be any thin film having corrosion resistance to droplets. In the present description, the example in which the corrosion-resistant thin film 325b is formed not only on the inner wall of the through hole 305 but also on the entire back surface of the substrate 301 on which the electrode is formed is shown. 30
The corrosion-resistant thin film 325b may be formed only on the inner wall 5.

In the next manufacturing procedure 9, FIGS. 19A and 19B
Next, only the drive electrode portion in the pad region is etched and removed from the corrosion-resistant thin film 325, the silicon diaphragm 312, and the insulating film 304 to form a pad portion 321. A liquid chamber cover 314 made of a glass plate or a metal plate on which the droplet nozzle holes 319 are formed by laser processing, or an etched silicon substrate is attached to complete the ink jet recording head 326 of the second embodiment.

The liquid chamber substrate is manufactured through the above-described manufacturing procedures 1 to 9,
A driving liquid chamber 318 formed by anisotropic etching corresponding to each droplet nozzle hole 319 and a common liquid chamber 316 for supplying a liquid thereto are formed. It is communicated by a road 317. Further, the common liquid chamber 316 is communicated through a liquid flow path 305 penetrating from the back surface where the droplet supply port 315 is formed to the front surface.

A corrosion-resistant structure in which the corrosion-resistant thin films 325a and 325b are formed on the surface of each member that comes into contact with the ink liquid is completed. In the electrostatic actuator configured as described above, when a drive voltage is applied to the drive electrode pad 321, the single crystal silicon diaphragm 312 and the drive electrode 3
Electrostatic force works during 21. Therefore, diaphragm 312 is
The liquid chamber 318 is bent in the direction of the drive electrode 321 and a negative pressure is generated in the liquid chamber 318. Thus, the liquid is supplied to the driving liquid chamber 318 from the common liquid chamber 316 via the flow path 317 for supplying the liquid.

Next, when the driving voltage is cut off, the single crystal silicon diaphragm 312 returns to the original position due to the rigidity of silicon. At this time, the ink liquid inside the driving liquid chamber 318 is pressurized and discharged from the droplet nozzle holes 319 in the 320 direction. In such an electrostatic actuator, when titanium nitride is used as the corrosion-resistant thin films 325a and 325b against droplets, the deflection amount of the 2 μm-thick diaphragm into which boron impurities of 1E19 / cm 3 or more are introduced and the injection characteristic liquid ( FIG. 20 shows the results of evaluating the variation between bits of the droplet ejection speed and the appropriate amount of liquid.

From this evaluation result, it can be seen that if the diaphragm 312 is bent when the corrosion-resistant thin film 325a is formed on the diaphragm 312, there is a variation in the injection characteristics between bits, which is a serious problem in practical use. . For this reason, when the corrosion-resistant thin films 325a and 325b are sequentially formed on the diaphragm 312, it is not preferable that the diaphragm 312 bend even a little. This tendency showed the same result when any of the thin films having corrosion resistance to droplets was used.

Next, FIG. 21 shows the results of evaluating the concentration of oxygen atoms contained in titanium nitride and the corrosion resistance to droplets when titanium nitride was used as the corrosion-resistant thin films 325a and 325b.

As shown in FIG. 21, when oxygen atoms were not contained in titanium nitride, no serious problem was caused in practical use. It can be seen that at least in the case of the included titanium nitride, the corrosion resistance is improved. In the case of titanium nitride containing 1% or more, it was found that the corrosion resistance was further improved.

From this, the corrosion-resistant thin films 325a and 325a
When titanium nitride is used for 25b, it is desirable that at least oxygen atoms are contained, and when titanium nitride containing 1% or more oxygen atoms is contained, it is further desirable.

Next, the configuration of the third embodiment will be described with reference to FIGS. As shown in FIGS. 22 to 25, in the configuration of the third embodiment, since the corrosion-resistant thin film 625 is laminated, pinholes generated in the corrosion-resistant thin film 625 due to dust are prevented, and the reliability is further improved. The case of a configuration is shown. Also, a single crystal silicon substrate which is a support for improving the adhesive strength when assembling the frame and the electrostatic actuator on the vibration plate, the inner and upper portions of the driving liquid chamber, the common liquid chamber and the liquid flow path, and the frame. 601 liquid supply port 6
15 shows an example in which a corrosion-resistant thin film is formed on the entire back surface including No. 15.

FIG. 22 is a cross-sectional view of the drive electrode section shown in FIG.
It is a longitudinal cross-sectional view which shows the -A 'cross section. FIG. 23 shows the PA of FIG.
It is a longitudinal cross-sectional view which shows the BB 'cross section which is a cross section of D area. FIG. 24 is a longitudinal sectional view showing a section taken along line CC 'of FIG. FIG. 25 is a cross section of the liquid supply port area of FIG.
It is a longitudinal section showing a section.

The electrostatic actuator according to the third embodiment is manufactured according to the process flow (procedure) shown in FIGS.

As shown in FIG. 22 to FIG.
Reference numeral 1 denotes a p-single-crystal silicon substrate having a plane orientation (100) and a resistivity of 10 to 30 Ω-cm. The drive electrode 621 is a titanium nitride film formed on a silicon oxide film 602 having a thickness of 2 μm on a single crystal silicon substrate 601 and having a depth of 0.4 μm and formed on an oxide film by a reactive sputtering method. And are insulated from each other.

The silicon oxide 602 is formed by a thermal oxidation method. Further, a 200 nm-thick silicon oxide film 604 is formed on the titanium nitride of the drive electrode by a plasma CVD method. This silicon oxide film 604
Is for securing insulation between the diaphragm 612 and the drive electrode 621.

Reference numeral 608 denotes a drive electrode 6 of the electrostatic actuator from which the silicon oxide film 604 has been removed by etching.
21 is a pad area for applying a driving voltage to the pad 21. A boron impurity atom formed by anisotropically etching a single crystal silicon substrate 511 having a plane orientation of (110) with KOH is 1E1
A 2 μm-thick diaphragm 612 containing 9 / cm 3 or more has a driving electrode 6 through a silicon oxide film 602 serving as a gap spacer.
21. A driving liquid chamber 618 formed by anisotropic etching of KOH and a common liquid chamber 616 for supplying a liquid thereto are formed in the plane orientation (110) single crystal silicon substrate 611, and both are communicated by a channel 617. ing.

On the other hand, the (100) single-crystal silicon substrate 601 on which the drive electrode 621 is formed is connected to the common liquid chamber 616 through a through hole 605 penetrating from the back surface to the front surface.
A liquid supply port 615 for supplying a liquid from the back side is formed in the driving liquid chamber 618 and the common liquid chamber 6 as described above.
16 is communicated by a liquid channel 617.

On the other hand, the surface of the liquid chamber substrate 611, the surface of the silicon diaphragm 612, the inside of the driving liquid chamber 618, the common liquid chamber 6
16, the surface of the liquid flow channel 617, the surface of the through flow channel 605, and the liquid supply port 615 for supplying the liquid from the back side.
Are formed on the entire back surface of the single-crystal silicon substrate 601 containing a silicon nitride film 625b, 625d made of titanium nitride having a thickness of 500.degree. The corrosion-resistant thin film 625a made of titanium nitride having a thickness of 500% and containing 15% of oxygen atoms formed by changing the conditions of
625c are sequentially formed.

At this time, the diaphragm 612 was not bent at all by buckling. Further, the droplet nozzle hole 61
A metal plate 614 on which 9 is formed is stuck on the liquid chamber. In such an electrostatic actuator, the diaphragm 612 is electrically grounded.
A drive voltage is applied to the drive electrode 621 via the drive electrode 621 to drive at a constant frequency. When a voltage is applied, an electrostatic attractive force acts between the diaphragm 612 and the drive electrode 621. Therefore, the diaphragm 6
12 is a corrosion-resistant thin film 625a, 6 made of titanium nitride.
Since no bending is caused by the buckling of 25b, it is sufficiently pulled toward the drive electrode by electrostatic attraction.

As a result, the inside of the driving liquid chamber 618 has a sufficient negative pressure. Therefore, the liquid connected to the liquid supply port 615 passes through the through channel 605, the common liquid chamber 616, and the channel 617.
The liquid is supplied to the driving liquid chamber 618 via

Further, the diaphragm 612 returns to the original position due to the rigidity of the silicon in accordance with the frequency of the driving voltage.
Thus, the inside of the driving liquid chamber 618 is pressurized. Therefore, the liquid inside the driving liquid chamber 618 is
9 is stably discharged in the direction of arrow 620.

Further, as a result of measuring the variation of the injection characteristics between the bits in this state, it was possible to obtain the injection characteristics with very good uniformity. In addition, as a result of performing a reliability test using droplets using the corrosion-resistant thin films 625a to 625d on which titanium nitride is laminated, no silicon, which is a constituent member of the electrostatic actuator of the present invention, was eluted in the droplets at all. It was confirmed that there was no reliability failure due to pinholes. Furthermore, since the corrosion-resistant thin films 625c and 625d made of titanium nitride are formed over the entire back surface of the silicon substrate 601, the bonding strength when assembling with a frame (not shown) is increased and reliability is improved. Example 1
It is even better than in the case of.

Next, an embodiment 4 in which the electrostatic actuator of the present invention (embodiments 1 to 3) is used in an ink jet recording apparatus.
This will be described with reference to FIGS. 26 and 27.

FIG. 26 is a perspective view showing the structure of a main part of an ink jet recording apparatus according to the present invention. FIG. 27 is a side view of the ink jet recording apparatus.

As shown in FIGS. 26 and 27, this ink jet recording apparatus includes a carriage 713 movable in the main scanning direction inside a recording apparatus main body 701, an ink jet recording head 714 mounted on the carriage 713, and a recording head 714. And a printing mechanism 702 including an ink cartridge 715 for supplying ink to the printer.

A paper feed cassette 704 capable of stacking a large number of sheets 703 from the front side is provided below the apparatus main body 701.
(Or the paper feed tray 705) can be freely inserted and removed. Further, the manual tray 705 for manually feeding the paper 703 can be opened, the paper 703 fed from the paper feed cassette 704 or the manual tray 705 is taken in, and a required image is printed by the printing mechanism 702. After recording, the output tray 7 mounted on the rear side
06 is discharged.

The printing mechanism 702 slides the carriage 713 in a main scanning direction as shown in FIG. 27 in a direction perpendicular to the sheet of FIG. 27 by a main guide rod 711 and a sub guide rod 712 which are guide members laid horizontally on left and right side plates (not shown). Hold. The carriage 713 includes yellow (Y), cyan (C),
A plurality of ink discharge ports are arranged in a direction intersecting the main scanning direction with a plurality of ink discharge ports arranged in a direction intersecting the main scanning direction, and a head 714 composed of ink jet heads discharging ink droplets of each color of magenta (M) and black (Bk) is directed downward. It is installed.

As the head 714, the electrostatic actuator of the present invention (Examples 1 to 3) was used as an ink jet head. Here, the carriage 713 is slidably fitted on the main guide rod 711 on the rear side (downstream side in the paper conveyance direction), and slidably mounted on the slave guide rod 712 on the front side (downstream side in the paper conveyance direction). It is location.

In order to move and scan the carriage 713 in the main scanning direction, a timing belt 720 is stretched between a driving pulley 718 rotated and driven by a main scanning motor 717 and a driven pulley 719. Is fixed to the carriage 713, and the carriage 713 is reciprocated by the forward and reverse rotation of the main scanning motor 717.

On the other hand, in order to transport the sheet 703 set in the sheet cassette 704 to the lower side of the head 714, a sheet feed roller 721 and a friction pad 722 for separating and feeding the sheet 703 from the sheet cassette 704,
3, a guide member 723 for guiding
A transport roller 724 that reverses and transports the sheet 3 and a transport roller 725 that is pressed against the peripheral surface of the transport roller 724 and a tip roller 726 that defines the angle at which the sheet 703 is sent out from the transport roller 724 are provided.

The transport roller 724 has a sub-scanning motor 727
Is driven to rotate via a gear train. Then, the sheet 703 sent from the transport roller 724 corresponding to the moving range of the carriage 713 in the main scanning direction is transferred to the recording head 7.
An image receiving member 729 is provided as a paper guide member for guiding the lower side of the sheet 14. On the downstream side of the printing receiving member 729 in the paper transport direction, a transport roller 731 and a spur 732 that are driven to rotate to transport the paper 703 in the paper discharge direction are provided. A roller 733 and a spur 734, and guide members 735 and 736 forming a paper discharge path are provided.

At the time of recording, by driving the recording head 714 according to the image signal while moving the carriage 713, ink is discharged onto the stopped paper 703 to record one line, and the paper 703 is moved by a predetermined amount. After transport, the next line is recorded. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 703 has reached the recording area, the recording operation is terminated and the sheet 703 is discharged.

As described above, by using the electrostatic actuators of Examples 1 to 3 in an ink jet recording apparatus,
As a result of printing using this ink jet recording apparatus, high-definition printing can be performed with low power consumption.

[0096]

As described above, according to the first aspect of the present invention, the thin film having corrosion resistance against the droplet is formed on the diaphragm and the liquid flow path penetrating from the back surface to the surface. Since the droplets are formed, the members constituting the electrostatic actuator and the droplets are completely shut off by the corrosion-resistant thin film. Substances such as ions eluted into the liquid do not deteriorate the quality of the droplet. When used as an ink recording head, deterioration of image quality can be prevented.

According to the second aspect of the present invention, since the corrosion-resistant thin film is formed on the entire back surface, the adhesive strength to an external support such as a frame is improved, and the yield of the assembling process is improved.

According to the third aspect of the present invention, since the corrosion-resistant thin film is formed on the side wall of the liquid chamber and on the upper part of the liquid chamber, the deterioration of the droplet due to the elution of the substance from the member constituting the side wall of the liquid chamber is eliminated. Further, the bonding strength with the droplet jet nozzle plate is improved, and the yield of assembly is improved.

According to the fourth aspect of the present invention, since the front and back surfaces of the corrosion-resistant thin film are formed in separate steps, it is possible to form a thin film whose front and back surfaces are separately controlled. Since the film quality and thickness can be changed, the margin of process design is widened.

According to the fifth aspect of the present invention, in an ink jet recording head for discharging ink droplets by a pressure wave by electrostatic force, a nozzle hole for discharging ink droplets and an ink flow path communicating with the nozzle holes are provided. 8. An anti-corrosion thin film formed on an ink liquid chamber, an ink flow path penetrating from the back surface to the front surface of the electrostatic actuator according to claim 1, a vibration plate, an ink liquid chamber side wall, an ink liquid chamber upper portion, and a back surface of the support. Therefore, an ink jet head that can handle any type of ink can be realized. In addition, since it is of an electrostatic type, an ink jet head having excellent low power consumption can be realized.

According to the invention set forth in claim 6, according to claim 10,
Since this is an ink jet recording apparatus using the ink jet head including the electrostatic actuator described above, it is possible to record a high quality image with low power consumption.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of an electrostatic actuator according to the present invention.

FIG. 2 is a longitudinal sectional view showing an AA ′ section in FIG. 1;

FIG. 3 is a longitudinal sectional view showing a BB ′ section in FIG. 1;

FIG. 4 is a longitudinal sectional view showing a section taken along the line CC ′ in FIG. 1;

FIG. 5 is a longitudinal sectional view showing a section taken along line DD ′ in FIG. 1;

FIG. 6 is a plan view of the electrostatic actuator according to the second embodiment.

FIG. 7 is a longitudinal sectional view showing an AA ′ section in FIG. 6;

FIG. 8 is a longitudinal sectional view showing a BB ′ section in FIG. 6;

FIG. 9 is a longitudinal sectional view showing a section taken along the line CC ′ in FIG. 6;

FIG. 10 is a longitudinal sectional view showing a section taken along line DD ′ in FIG. 6;

FIG. 11 is a manufacturing procedure 1 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 12 is a manufacturing procedure 2 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 13 is a manufacturing procedure 3 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 14 is a manufacturing procedure 4 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 15 is a manufacturing procedure 5 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 16 is a manufacturing procedure 6 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 17 is a manufacturing procedure 7 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 18 is a manufacturing procedure 8 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 19 is a manufacturing procedure 9 of the electrostatic actuator according to the second embodiment.
FIG.

FIG. 20 is a diagram illustrating a result of evaluating a variation between bits of a flexure amount of a diaphragm and ejection characteristics (a droplet ejection speed and a proper liquid amount).

FIG. 21 is a graph showing the results of evaluating the concentration of oxygen atoms contained in titanium nitride and the corrosion resistance to droplets when titanium nitride was used as the corrosion-resistant thin film.

FIG. 22 is a longitudinal sectional view showing an AA ′ section, which is a section of the drive electrode unit in FIG. 1;

23 is a longitudinal sectional view showing a BB ′ section, which is a section of the PAD region in FIG. 1;

FIG. 24 is a longitudinal sectional view showing a section taken along the line CC ′ of FIG. 1;

FIG. 25 is a vertical sectional view showing a section taken along line DD ′ of the liquid supply port region in FIG. 1;

FIG. 26 is a perspective view illustrating a main configuration of an inkjet recording apparatus according to the present invention.

FIG. 27 is a side view of the ink jet recording apparatus.

[Explanation of symbols]

101, 201, 301, 601 Single crystal silicon substrate 102, 202, 302, 602 Silicon oxide 104, 204, 304, 604 Insulating film 111, 211, 311, 611 Single crystal silicon substrate 112, 212, 312, 612 Silicon diaphragm 114, 214, 314, 614 Cover plate 115, 215, 315, 615 Liquid supply port 116, 216, 316, 616 Common liquid chamber 117, 217, 317, 617 Liquid flow path 118, 218, 317, 617 Driving liquid chamber 119 , 219, 319, 619 Droplet nozzle holes 121, 221, 321 and 621 Drive electrodes 125a, 125b, 225a, 225b, 325a,
325b, 625a to 625d Corrosion-resistant thin film 701 Recording device main body 702 Printing mechanism 713 Carriage 714 Ink jet recording head 715 Ink cartridge 703 Paper 704 Paper feed cassette

Claims (6)

[Claims] A liquid flow path penetrated from a surface provided with a nozzle hole for discharging liquid droplets to a back surface of a support communicating with a liquid supply side, and provided so as to be in contact with a liquid flowing through the liquid flow path. And an electrode provided opposite to the diaphragm, the electrode being configured to generate electrostatic attraction by applying a voltage to deform the diaphragm, and to use a repulsive force accompanying a deformation operation of the diaphragm. An electrostatic actuator that introduces a liquid and discharges a droplet from the nozzle hole, wherein a thin film having corrosion resistance to the droplet is formed on the liquid flow path in contact with the droplet and the diaphragm. Characteristic electrostatic actuator. 2. The electrostatic actuator according to claim 1, wherein a corrosion-resistant thin film is formed on the entire back surface of the support facing the liquid supply side. 3. The electrostatic actuator according to claim 1, wherein a thin film having corrosion resistance is formed on an inner wall of the liquid chamber formed between the diaphragm and the nozzle hole. 4. A liquid flow path of the electrostatic actuator, and
A method for manufacturing an electrostatic actuator, comprising forming a first thin film having corrosion resistance on a diaphragm and a second thin film having corrosion resistance on a back surface of the support in separate steps. 5. An ink jet recording head for ejecting ink droplets of an ink liquid chamber from a nozzle hole by a pressure wave of a vibration plate driven by electrostatic force of an electrostatic actuator, wherein the vibration plate of the electrostatic actuator and the ink An ink jet recording head, wherein a thin film having corrosion resistance is formed on an inner wall of a liquid chamber and a back surface of a support. 6. A recording medium conveying means for conveying a recording medium on which an ink image is to be recorded, and an ink droplet in an ink liquid chamber is ejected from a nozzle hole by a pressure wave of a diaphragm driven by electrostatic force of an electrostatic actuator. An ink jet recording apparatus for recording an ink image, comprising: an ink jet recording head that discharges onto a recording medium conveyed by the recording medium conveying means; wherein the ink jet recording head includes a vibration plate and an ink liquid chamber. An ink jet recording apparatus wherein a thin film having corrosion resistance is formed on an inner wall and a back surface of a support.