JP2004087547A - Piezoelectric actuator and manufacturing method therefor, ink jet head, and ink jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent migration from in a piezoelectric actuator. <P>SOLUTION: The piezoelectric actuator has a diaphragm 26 made of Cr and a common electrode 27 formed of Cu on the diaphragm 26, a piezoelectric body 29 formed of Pb(Zr, Ti)O3 on the common electrode 27, an individual electrode formed of Pt on the piezoelectric body 29, and a wire 34 for the individual electrode which is formed on the piezoelectric body 29 and connected to the individual electrode. The piezoelectric body 29 comprises a lower piezoelectric body 29a and an upper piezoelectric body 39b. The lower piezoelectric body 29a is formed on the common electrode 27. The upper piezoelectric body 29b is formed on the lower piezoelectric body 29a. The composition rate of Pb of the upper piezoelectric body 29b is lower than the composition rate of Pb of the lower piezoelectric body 29a. The wire 34 for the individual electrode is connected to one end of each individual electrode and a voltage input terminal part for applying voltages to respective individual electrodes. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric actuator, a method for manufacturing the same, an inkjet head, and an inkjet recording apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an ink jet head that performs recording by using a piezoelectric effect of a piezoelectric body has been known.
[0003]
This type of ink jet head includes a piezoelectric actuator in which a common electrode layer, a PZT layer, a plurality of individual electrodes, and an individual electrode layer having a plurality of individual electrode wirings are sequentially stacked, and an ink passage in which a pressure chamber is formed. A substrate. A vibration plate is provided on one surface of the piezoelectric actuator. This diaphragm is adhered on the ink flow path forming substrate with an adhesive. Each individual electrode is connected to a plurality of voltage input terminals connected to a driver IC or the like via each individual electrode wiring. When the ink is ejected, a voltage is applied to the common electrode layer and the individual electrode layers, whereby the PZT layer expands and contracts. When the expansion and contraction are restricted by the diaphragm, the piezoelectric actuator bends and deforms in the laminating direction. The volume of the pressure chamber changes due to the bending deformation, and ink in the pressure chamber is ejected from the nozzle.
[0004]
[Problems to be solved by the invention]
By the way, at the time of driving the ink jet head, the on / off switching of the voltage applied to each individual electrode is individually controlled. Therefore, when a voltage is applied to a certain individual electrode, a voltage may not be applied to an adjacent individual electrode, and a state where the voltage is applied to the ground may occur. At this time, a potential difference occurs between the adjacent individual electrodes, and migration may occur between the individual electrode wirings. This is considered for the following reasons. In a manufacturing process of an inkjet head, when a PZT layer is formed on an individual electrode layer formed on a substrate, the material of the individual electrode layer may diffuse into a surface layer of the PZT layer on the individual electrode layer side. Further, the composition ratio of the PZT layer should be Pb: (Zr + Ti): O = 1: 1: 3. However, in the firing step when forming the PZT layer on the individual electrode layer, PbO precipitates at the grain boundaries of the crystals of the PZT layer, and the composition ratio of the PZT layer is Pb: (Zr + Ti): O = 1.5: 1: It was 3.6, and the composition ratio of Pb was high. Here, when a voltage is applied to both electrode layers of the inkjet head as described above, or a voltage difference is generated between adjacent individual electrodes by individually controlling the voltage applied to each individual electrode, the PZT layer is individually The material of the individual electrode layer or Pb is deposited on the surface on the electrode layer side. Then, migration occurs between the individual electrode wires due to the material of the deposited individual electrode layer or Pb. Then, when the migration proceeds, a short circuit occurs between the individual electrode wirings, and the reliability of the inkjet head decreases.
[0005]
Similarly, migration may occur between the common electrode layer and the individual electrode layer. Then, when the migration proceeds, a short circuit occurs between the common electrode layer and the individual electrode layer, and the reliability of the ink jet head decreases.
[0006]
The present invention has been made in view of the above, and an object of the present invention is to provide a technique for preventing the occurrence of migration in a piezoelectric actuator.
[0007]
[Means for Solving the Problems]
A piezoelectric actuator according to the present invention includes a first electrode layer, a piezoelectric layer formed on the first electrode layer, and a voltage formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the first electrode layer. A piezoelectric actuator comprising: a second electrode layer, wherein the piezoelectric layer is formed on the first electrode layer, and includes a first electrode layer-side piezoelectric layer containing Pb; A second electrode layer-side piezoelectric layer that is formed, contains Pb, and has a lower composition ratio of Pb than the first electrode layer-side piezoelectric layer.
[0008]
Accordingly, the composition ratio of Pb in the second electrode layer side piezoelectric layer is lower than that of the first electrode layer side piezoelectric layer. Therefore, when a voltage is applied between both electrode layers, the second electrode layer side Pb hardly precipitates on the side surface. Therefore, according to the present invention, migration between the first electrode layer and the second electrode layer can be prevented, and the reliability of the inkjet head can be improved.
[0009]
In the piezoelectric actuator according to the present invention, the first electrode layer has a common electrode layer, and the second electrode layer has a plurality of individualized individual electrodes, and the individual electrodes correspond to the individual electrodes and the individual electrodes. And a plurality of individual electrode wirings connected to the plurality of voltage input terminals provided.
[0010]
Accordingly, since the composition ratio of Pb in the second electrode layer side piezoelectric layer is lower than that in the first electrode layer side piezoelectric layer, when a voltage is applied between both electrode layers or the voltage applied to each individual electrode is individually controlled. Accordingly, when a potential difference occurs between adjacent individual electrodes, Pb is unlikely to be deposited on the surface of the piezoelectric layer on the second electrode layer side, that is, on the surface of the individual electrode and the individual electrode wiring side. Therefore, according to the present invention, migration between the individual electrode wires can be prevented.
[0011]
A piezoelectric actuator according to the present invention includes a common electrode layer, a piezoelectric layer formed on the common electrode layer, and an individual electrode layer formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the common electrode layer. A piezoelectric actuator comprising: a first piezoelectric layer formed on the common electrode layer; and a second piezoelectric layer formed on the first piezoelectric layer. The electrode layer has a plurality of individualized individual electrodes and a plurality of individual electrode wirings connecting the individual electrodes and a plurality of voltage input terminals provided corresponding to the individual electrodes, The second piezoelectric layer is individualized so as to be located at a portion corresponding to each of the individual electrodes and each of the individual electrode wires.
[0012]
By the way, in the manufacturing process of a piezoelectric actuator, when a piezoelectric layer is formed on an individual electrode layer formed on a substrate, or when an individual electrode layer is formed on a piezoelectric layer formed on a common electrode layer, In some cases, the material of the individual electrode layer diffuses into the surface layer on the individual electrode layer side of the layer. At this time, when a voltage is applied between the common electrode layer and the individual electrode layer, or a voltage difference is generated between adjacent individual electrodes by controlling the voltage applied to each individual electrode individually, the The material of the individual electrode layer is deposited on the surface on the electrode layer side. Then, migration occurs between the individual electrode wires due to the material of the deposited individual electrode layer.
[0013]
Here, according to the present invention, the second piezoelectric layer formed on the first piezoelectric layer is individualized so as to be located at a portion corresponding to each individual electrode and each individual electrode wiring. The second piezoelectric layer is a layer in which the material of the individual electrode layer is diffused to the piezoelectric layer side in the manufacturing process of the piezoelectric actuator, and a portion other than each individual electrode and each individual electrode wiring is removed. is there. Therefore, when a voltage is applied between the common electrode layer and the individual electrode layer, or when a potential difference is generated between adjacent individual electrodes by controlling the voltage applied to each individual electrode individually, the first The material of the individual electrode layer hardly precipitates between the individual electrode wirings on the surface of the piezoelectric layer on the individual electrode layer side.
[0014]
Further, since only the electrode material diffusion layer of the piezoelectric layer, that is, only the very surface of the piezoelectric layer is removed, the influence of side etching and etching residue due to etching is small.
[0015]
As described above, according to the present invention, migration between the individual electrode wirings can be prevented, and a decrease in reliability due to etching can be prevented.
[0016]
A piezoelectric actuator according to the present invention includes a common electrode layer, a piezoelectric layer formed on the common electrode layer, and an individual electrode layer formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the common electrode layer. Wherein the individual electrode layer comprises a plurality of individualized individual electrodes and a plurality of individual electrodes connected to the plurality of voltage input terminals provided corresponding to the individual electrodes. , And the piezoelectric layer is individualized such that the piezoelectric layer is located at a portion corresponding to each of the individual electrodes and each of the individual electrode wires.
[0017]
As a result, the piezoelectric layer is individualized so as to be located at a portion corresponding to each individual electrode and each individual electrode wiring. Therefore, the piezoelectric layer is located between the piezoelectric layers located at portions corresponding to each individual electrode wiring. not exist. Therefore, when a voltage is applied between the common electrode layer and the individual electrode layer, or when a potential difference occurs between adjacent individual electrodes by controlling the voltage applied to each individual electrode individually, The material of the individual electrode layer does not precipitate between the electrode wirings.
[0018]
By the way, if the displaced portion and the non-displaced portion of the piezoelectric layer continue without being individualized, stress concentration occurs at the continuous portion, and cracks easily occur in the piezoelectric layer.
[0019]
Here, according to the present invention, since the piezoelectric layer exists only at the position corresponding to each individual electrode and each individual electrode wiring, the entire piezoelectric layer is uniformly displaced when a voltage is applied, and there is no non-displaced portion. . Therefore, cracks are less likely to occur in the piezoelectric layer when a voltage is applied.
[0020]
As described above, according to the present invention, it is possible to prevent migration between the individual electrode wirings, prevent cracks in the piezoelectric layer, and obtain a highly reliable piezoelectric actuator.
[0021]
An inkjet head according to the present invention includes the piezoelectric actuator according to claim 1.
[0022]
An ink jet head according to the present invention is formed on the piezoelectric actuator according to claim 2 and the first electrode layer side surface or the second electrode layer side surface of the piezoelectric actuator, and includes a plurality of nozzles and each of the nozzles. An ink flow path forming member formed with a plurality of communicating pressure chambers, wherein the individual electrodes are located at portions corresponding to the pressure chambers.
[0023]
An ink jet head according to the present invention is formed on the surface of the piezoelectric actuator according to claim 3 or 4 on the surface on the common electrode layer side or on the surface on the individual electrode layer side of the piezoelectric actuator. An ink flow path forming member formed with a plurality of communicating pressure chambers, wherein the individual electrodes are located at portions corresponding to the pressure chambers.
[0024]
An ink jet recording apparatus according to the present invention includes the ink jet head according to any one of claims 5 to 8.
[0025]
A method of manufacturing a piezoelectric actuator according to the present invention includes a step of forming an individual electrode layer on a first substrate, a step of forming an individual electrode layer-side piezoelectric layer containing Pb on the individual electrode layer, and a step of forming the individual electrode layer. Forming a common electrode layer side piezoelectric layer containing Pb and having a higher composition ratio of Pb than the individual electrode layer side piezoelectric layer on the side piezoelectric layer, and forming a common electrode layer on the common electrode layer side piezoelectric layer Performing, fixing a second substrate on the common electrode layer, removing the first substrate, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings. And a process.
[0026]
A method of manufacturing a piezoelectric actuator according to the present invention includes forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate. Forming a common electrode layer-side piezoelectric layer containing Pb on the common electrode layer; and forming Pb on the common electrode layer-side piezoelectric layer, wherein the composition ratio of Pb is lower than that of the common electrode layer-side piezoelectric layer. Forming an individual electrode layer side piezoelectric layer, forming an individual electrode layer on the individual electrode layer side piezoelectric layer, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings And a step of performing
[0027]
In the method for manufacturing a piezoelectric actuator according to the present invention, a step of forming an individual electrode layer on a first substrate, a step of forming a piezoelectric layer on the individual electrode layer, and a step of forming a common electrode layer on the piezoelectric layer Fixing a second substrate on the common electrode layer, removing the first substrate, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings. And removing a surface layer on the side of the individual electrode layer of the piezoelectric layer located in a portion other than a portion corresponding to each individual electrode and each individual electrode wiring.
[0028]
A method of manufacturing a piezoelectric actuator according to the present invention includes forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate. Forming a piezoelectric layer on the common electrode layer, forming an individual electrode layer on the piezoelectric layer, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings. And a step of removing a surface layer on the side of the individual electrode layer of the piezoelectric layer located in a portion other than a portion corresponding to each individual electrode and each individual electrode wiring.
[0029]
In the method for manufacturing a piezoelectric actuator according to the present invention, a step of forming an individual electrode layer on a first substrate, a step of forming a piezoelectric layer on the individual electrode layer, and a step of forming a common electrode layer on the piezoelectric layer Fixing a second substrate on the common electrode layer, removing the first substrate, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings. And a step of individualizing a portion of the piezoelectric layer corresponding to each individual electrode and each individual electrode wiring.
[0030]
A method of manufacturing a piezoelectric actuator according to the present invention includes forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate. Forming a piezoelectric layer on the common electrode layer, forming an individual electrode layer on the piezoelectric layer, and individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings. And a step of individualizing portions of the piezoelectric layer corresponding to the individual electrodes and the individual electrode wirings.
[0031]
【The invention's effect】
According to the piezoelectric actuator of the present invention, the composition ratio of Pb in the second electrode layer-side piezoelectric layer is lower than that in the first electrode layer-side piezoelectric layer. Pb hardly precipitates on the surface of the piezoelectric layer on the side of the second electrode layer. Therefore, migration between the first electrode layer and the second electrode layer can be prevented, and the reliability of the inkjet head can be improved.
[0032]
According to the piezoelectric actuator of the present invention, since the composition ratio of Pb is lower in the individual electrode layer side piezoelectric layer than in the common electrode layer side piezoelectric layer, when a voltage is applied between the common electrode layer and the individual electrode layer, or When a potential difference is generated between adjacent individual electrodes by individually controlling the voltage applied to each individual electrode, Pb hardly precipitates on the surface of the individual electrode layer side piezoelectric layer on the individual electrode layer side. Therefore, migration between the individual electrode wirings can be prevented. Further, the reliability of the inkjet head can be improved.
[0033]
According to the piezoelectric actuator according to the present invention, the second piezoelectric layer formed on the first piezoelectric layer is individualized so as to be located at a portion corresponding to each individual electrode and each individual electrode wiring. That is, since the second piezoelectric layer, which is the diffusion layer of the electrode material, is removed except for the portion corresponding to each individual electrode and each individual electrode wiring, a voltage is applied between the common electrode layer and the individual electrode layer. Or when a potential difference is generated between adjacent individual electrodes by individually controlling the voltage applied to each individual electrode, the potential between the individual electrode wirings on the surface of the first piezoelectric layer on the individual electrode layer side is reduced. The material of the individual electrode layer is not easily deposited. Therefore, migration between the individual electrode wirings can be prevented.
[0034]
According to the piezoelectric actuator according to the present invention, since the piezoelectric layer is individualized so as to be located at a portion corresponding to each individual electrode and each individual electrode wiring, it is located at a portion corresponding to each individual electrode wiring. There is no piezoelectric layer between the piezoelectric layers. Therefore, when a voltage is applied between the common electrode layer and the individual electrode layer, or when a voltage difference is generated between adjacent individual electrodes by controlling the voltage applied to each individual electrode individually, Since the material of the individual electrode layer does not precipitate between the electrode wires, migration between the individual electrode wires can be prevented.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
As shown in FIG. 1, an ink jet head 1 according to the present embodiment is incorporated in an ink jet printer 3 as an ink jet type recording apparatus, and performs recording by causing ejected ink droplets to land on a recording medium 5 such as paper. is there.
[0036]
The ink jet head 1 is mounted on a carriage 9 that reciprocates along a carriage shaft 7 and reciprocates in the main scanning direction X together with the carriage 9. The roller 10 is configured to convey the recording medium 5 in the sub-scanning direction Y each time the carriage 9 moves by one scan in the main scanning direction X.
[0037]
As shown in FIG. 2, the inkjet head 1 includes a head body 17 in which a common ink chamber 11, a plurality of pressure chambers 19, and a plurality of nozzles 15 are formed, and a piezoelectric body that applies pressure to the ink in the pressure chamber 19. An actuator 21 is provided.
[0038]
The pressure chambers 19 of the head main body 17 are provided at predetermined intervals along the sub-scanning direction Y. The pressure chamber 19 is formed in a substantially rectangular shape whose opening cross section (XY cross section) is elongated in the main scanning direction X. An ink supply port 23 connected to the common ink chamber 11 is formed at one longitudinal end (right end in FIG. 2) at the bottom of the pressure chamber 19, and a nozzle 15 is provided at the other end (left end in FIG. 2). Is formed.
[0039]
As shown in FIGS. 2 to 4, the piezoelectric actuator 21 includes a vibration plate 26 made of 2 μm Cr, a common electrode 27 formed on the vibration plate 26 and made of 5.5 μm thick Cu, and a common electrode 27. 3 μm thick Pb (Zr, Ti) O formed on top ₃ , A 0.1 μm thick individual electrode 33 made of Pt formed on the piezoelectric body 29, and a 0.1 μm thick formed on the piezoelectric body 29 and connected to the individual electrode 33. 2 (not shown in FIG. 2). In the present invention, the first electrode layer and the common electrode layer are constituted by the common electrode 27, and the second electrode layer and the individual electrode layer are constituted by the individual electrode 33 and the individual electrode wiring.
[0040]
The piezoelectric body 29 includes a lower piezoelectric body 29a and an upper piezoelectric body 29b. The lower piezoelectric body 29a is formed on the common electrode 27. The upper piezoelectric body 29b is formed on the lower piezoelectric body 29a, and the composition ratio of Pb is lower than the composition ratio of Pb of the lower piezoelectric body 29a. The common electrode layer side piezoelectric layer in the present invention is constituted by a lower piezoelectric body 29a, and the individual electrode layer side piezoelectric layer is constituted by an upper piezoelectric body 29b.
[0041]
The individual electrode wiring 34 is connected to one end of each individual electrode 33 and a voltage input terminal (not shown) for applying a voltage to each individual electrode 33.
[0042]
(Method of manufacturing inkjet head)
Next, a method of manufacturing the inkjet head 1 will be described with reference to FIGS. The method of manufacturing the inkjet head 1 described below is called a transfer method.
[0043]
First, as shown in FIG. 5A, an upper electrode 49 made of Pt is formed on a MgO substrate 47 by sputtering or vapor deposition. The first substrate according to the present invention is constituted by the MgO substrate 47.
[0044]
Next, as shown in FIG. 5B, Pb (Zr, Ti) O is formed on the upper electrode 49 by sputtering or vapor deposition. ₃ The upper piezoelectric body 29b made of is formed. The film forming temperature of the upper piezoelectric body 29b is 590 ° C. Here, since the film forming temperature of the upper piezoelectric body 29b is higher than the film forming temperature of the lower piezoelectric body 29a described later, the composition ratio of Pb in the upper piezoelectric body 29b is lower than the composition ratio of Pb in the lower piezoelectric body 29a.
[0045]
Next, as shown in FIG. 5C, Pb (Zr, Ti) O is formed on the upper piezoelectric body 29b by sputtering or vapor deposition. ₃ A lower piezoelectric body 29a made of is formed. The film forming temperature of the lower piezoelectric body 29a is 540 ° C. In order to grow the lower piezoelectric body 29a in a perovskite structure, the film forming temperature of the lower piezoelectric body 29a is preferably 540 ° C. or higher.
[0046]
Next, as shown in FIG. 5D, a common electrode 27 made of Cu is formed on the lower piezoelectric body 29a.
[0047]
Next, as shown in FIG. 6A, a diaphragm 26 made of Cr is formed on the common electrode 27 by sputtering or vapor deposition.
[0048]
Next, as shown in FIG. 6B, the head body 17 in which the pressure chamber 19 is formed on the vibration plate 26 is electrodeposited. The second substrate in the present invention is constituted by the head main body 17.
[0049]
Next, as shown in FIG. 6C, the MgO substrate 47 is removed by etching or the like.
[0050]
Finally, as shown in FIG. 6D, the individual electrodes 33 and the individual electrode wirings 34 are formed by individualizing the upper electrodes 49 corresponding to the portions where the individual electrodes 33 and the individual electrode wirings 34 are formed by etching or the like. Form.
[0051]
(Operation method of inkjet head)
Here, an operation method of the inkjet head 1 according to the present embodiment will be described. First, a voltage is applied to the common electrode 27 and the individual electrodes 33. When a voltage is applied to both electrodes 27 and 33, piezoelectric body 29 expands and contracts. When the expansion and contraction are restricted by the vibration plate 26, the piezoelectric actuator 21 bends and deforms in the stacking direction. The volume in the pressure chamber 19 changes due to the bending deformation, and the ink in the pressure chamber 19 is ejected from the nozzle 15 through the ink flow path 25.
[0052]
According to the present embodiment, since the composition ratio of Pb in the upper piezoelectric body 29b is lower than the composition ratio of Pb in the lower piezoelectric body 29a, when a voltage is applied to both electrodes 27 and 33, or when a voltage is applied to each individual electrode 33. By controlling the applied voltage individually, when a potential difference occurs between the adjacent individual electrodes 33 or between the individual electrode wirings 34, Pb hardly precipitates on the upper surface of the upper piezoelectric body 29b. Therefore, migration between the common electrode 27 and the individual electrode 33 and the individual electrode wiring 34 can be prevented, and the reliability of the inkjet head 1 can be improved.
[0053]
Further, since the composition ratio of Pb in the upper piezoelectric body 29b is lower than the composition ratio of Pb in the lower piezoelectric body 29a, when a voltage is applied to both electrodes 27 and 33, or a voltage applied to each individual electrode 33 is individually When the control causes a potential difference between the adjacent individual electrodes 33 or between the individual electrode wirings 34, Pb hardly precipitates on the upper surface of the upper piezoelectric body 29b. Therefore, migration between the individual electrode wirings 34 can be prevented.
[0054]
According to the present embodiment, the piezoelectric body 29 is made of Pb (Zr, Ti) O ₃ , A piezoelectric body containing Pb, for example, PbTiO ₃ Or PMN-PZT or the like.
[0055]
(Embodiment 2)
The piezoelectric actuator according to the present embodiment is manufactured by a so-called direct construction method, and has substantially the same configuration as the piezoelectric actuator of the first embodiment. Hereinafter, a configuration different from the first embodiment will be described.
[0056]
As shown in FIG. 7, the piezoelectric actuator 21 includes a diaphragm 26 made of 2 μm Cr, a common electrode 27 formed of 5.5 μm thick Cu formed on the diaphragm 26, and formed on the common electrode 27. Adhesive layer 32 made of Ti having a thickness of 50 nm, Pt-Ti alloy layer 36 having a thickness of 0.2 μm formed on adhesive layer 32, and 50 nm having a thickness of 50 nm formed on Pt-Ti alloy layer 36. PLT layer 28 and Pb (Zr, Ti) O 3 μm thick formed on PLT layer 28 ₃ And an individual electrode 33 made of Pt having a thickness of 0.2 μm formed on the piezoelectric body 29 and an individual electrode wiring 34 connected to the individual electrode 33.
[0057]
(Method of manufacturing inkjet head)
Next, a method for manufacturing the inkjet head 1 will be described with reference to FIGS. The method of manufacturing the ink jet head 1 described below is called a direct method.
[0058]
First, as shown in FIG. 8A, the diaphragm 26 made of Cr is formed on a Si substrate 48.
[0059]
Next, as shown in FIG. 8B, a common electrode 27 made of Cu is formed on the diaphragm 26.
[0060]
Next, as shown in FIG. 8C, an adhesive layer 32 made of Ti is formed on the common electrode 27.
[0061]
Next, as shown in FIG. 8D, a Pt—Ti alloy layer 36 is formed on the adhesive layer 32.
[0062]
Next, as shown in FIG. 8E, the PLT layer 28 is formed on the Pt—Ti alloy layer 36.
[0063]
Next, as shown in FIG. 9A, Pb (Zr, Ti) O is formed on the PLT layer 28 by sputtering or vapor deposition. ₃ A lower piezoelectric body 29a made of is formed. The film forming temperature of the lower piezoelectric body 29a is 540 ° C.
[0064]
Next, as shown in FIG. 9B, Pb (Zr, Ti) O is formed on the lower piezoelectric body 29a by sputtering or vapor deposition. ₃ The upper piezoelectric body 29b made of is formed. The film forming temperature of the upper piezoelectric body 29b is 590 ° C.
[0065]
Next, as shown in FIG. 9C, an upper electrode 49 made of Pt is formed on the upper piezoelectric body 29b by sputtering or vapor deposition.
[0066]
Next, as shown in FIG. 9D, the upper electrode 49 corresponding to the part where the individual electrode 33 and the individual electrode wiring 34 are formed is individualized by etching or the like, so that the individual electrode 33 and the individual electrode wiring 34 are formed. Form. Lastly, the Si substrate 48 is processed to form the head main body 17 in which the pressure chamber 19 is formed. Note that a stopper layer (not shown) may be provided between the Si substrate 48 and the vibration plate 26 in order to prevent the vibration plate 26 from being damaged when the pressure chamber 19 is formed by processing the Si substrate 48.
[0067]
In this embodiment, the same effects as in the first embodiment can be obtained.
[0068]
(Embodiment 3)
The piezoelectric actuator according to the present embodiment has the same structure as the piezoelectric actuator of the first embodiment except that the surface layer of the piezoelectric body other than the portions corresponding to the individual electrodes and the wiring for the individual electrodes is removed. Hereinafter, a configuration different from the first embodiment will be described.
[0069]
As shown in FIG. 10, the piezoelectric actuator 21 includes a vibration plate 26 made of 2 μm Cr, a common electrode 27 made of 5.5 μm thick Cu formed on the vibration plate 26, and a common electrode 27 formed on the common electrode 27. 3 μm thick Pb (Zr, Ti) O ₃ , A 0.1 μm thick individual electrode 33 made of Pt formed on the piezoelectric body 29, and a 0.1 μm thick formed on the piezoelectric body 29 and connected to the individual electrode 33. And an individual electrode wiring 34 made of Pt.
[0070]
The surface portion of the piezoelectric body 29 on the side of the individual electrode 33 constitutes an electrode material diffusion layer 30. The electrode material diffusion layer 30 is composed of Pb (Zr, Ti) O on the upper electrode 49 made of Pt. ₃ This is a layer in which Pt, which is the material of the upper electrode 49, is diffused when the piezoelectric body 29 is formed. Portions of the electrode material diffusion layer 30 other than those corresponding to the individual electrodes 33 and the individual electrode wires 34 are removed. In the present invention, the first piezoelectric layer is constituted by a piezoelectric body 29 other than the electrode material diffusion layer 30, and the second piezoelectric layer is constituted by the electrode material diffusion layer 30.
[0071]
(Method of manufacturing inkjet head)
Next, a method for manufacturing the inkjet head 1 will be described with reference to FIGS.
[0072]
First, as shown in FIG. 11A, an upper electrode 49 made of Pt is formed on an MgO substrate 47 by sputtering or vapor deposition.
[0073]
Next, as shown in FIG. 11B, Pb (Zr, Ti) O is formed on the upper electrode 49 by sputtering or vapor deposition. ₃ Is formed. At this time, Pt, which is the material of the upper electrode 49, diffuses into the surface layer of the piezoelectric body 29 on the upper electrode 49 side. This surface layer constitutes the electrode material diffusion layer 30.
[0074]
Next, as shown in FIG. 11C, a common electrode 27 made of Cu is formed on the piezoelectric body 29.
[0075]
Next, as shown in FIG. 11D, a diaphragm 26 made of Cr is formed on the common electrode 27 by sputtering, vapor deposition, or the like.
[0076]
Next, as shown in FIG. 12A, the head body 17 in which the pressure chamber 19 is formed on the vibration plate 26 is electrodeposited.
[0077]
Next, as shown in FIG. 12B, the MgO substrate 47 is removed by etching or the like.
[0078]
Next, as shown in FIG. 12C, the upper electrode 49 corresponding to the part where the individual electrode 33 and the individual electrode wiring 34 are formed is individualized by etching or the like, so that the individual electrode 33 and the individual electrode wiring 34 are formed. Form.
[0079]
Finally, as shown in FIG. 12D, the surface layer portion of the piezoelectric body 29 on the individual electrode 33 side, which is located in a portion other than the portion corresponding to the individual electrode 33 and the individual electrode wiring 34, that is, the electrode material diffusion layer 30 is removed by dry etching. The thickness of the electrode material diffusion layer 30 is 100 nm.
[0080]
According to the present embodiment, even when Pt of the material of the upper electrode 49 is diffused into the surface layer of the piezoelectric body 29 on the individual electrode 33 side when the piezoelectric body 29 is formed on the upper electrode 49, the individual electrode 33 and the individual Since the electrode material diffusion layer 30 located in a portion other than the electrode wiring 34 has been removed, the voltage applied to both electrodes 27 and 33 or the voltage applied to each individual electrode 33 is individually controlled. Thus, even if a potential difference occurs between the adjacent individual electrodes 33 or between the individual electrode wirings 34, Pt does not precipitate between the individual electrode wirings 34 on the upper surface of the piezoelectric body 29. In addition, since only the electrode material diffusion layer 30, that is, the surface of the piezoelectric body 29 is removed, the influence of side etching by etching and an etching residue is small. Therefore, migration between the individual electrode wirings 34 can be prevented, and a decrease in reliability due to etching can be prevented.
[0081]
According to the present embodiment, the inkjet head 1 is manufactured by the transfer method, but may be manufactured by the direct method.
[0082]
Further, the piezoelectric body 29 is formed on the first piezoelectric body formed on the common electrode 27 and the first piezoelectric body, and the composition ratio of Pb is lower than the composition ratio of Pb of the first piezoelectric body. Two piezoelectric bodies may be used.
[0083]
(Embodiment 4)
The piezoelectric actuator according to the present embodiment is obtained by individualizing a piezoelectric body located at a portion corresponding to an individual electrode and a wiring for an individual electrode, and has substantially the same configuration as the piezoelectric actuator of the third embodiment. Hereinafter, a configuration different from the third embodiment will be described.
[0084]
As shown in FIG. 13, the piezoelectric actuator 21 includes a vibration plate 26 made of 2 μm Cr, a common electrode 27 made of 5.5 μm thick Cu formed on the vibration plate 26, and a common electrode 27 formed on the common electrode 27. 3 μm thick Pb (Zr, Ti) O ₃ , A 0.1 μm thick individual electrode 33 made of Pt formed on the piezoelectric body 29, and a 0.1 μm thick formed on the piezoelectric body 29 and connected to the individual electrode 33. And an individual electrode wiring 34 made of Pt. The piezoelectric body 29 is individualized so as to be located at a portion corresponding to the individual electrode 33 and the individual electrode wiring 34.
[0085]
(Method of manufacturing inkjet head)
Next, a method for manufacturing the inkjet head 1 will be described with reference to FIGS.
[0086]
First, as shown in FIG. 14A, an upper electrode 49 made of Pt is formed on an MgO substrate 47 by sputtering or vapor deposition.
[0087]
Next, as shown in FIG. 14B, Pb (Zr, Ti) O is formed on the upper electrode 49 by sputtering or vapor deposition. ₃ Is formed. At this time, Pt, which is the material of the upper electrode 49, diffuses into the surface layer of the piezoelectric body 29 on the upper electrode 49 side. This surface layer constitutes the electrode material diffusion layer 30.
[0088]
Next, as shown in FIG. 14C, a common electrode 27 made of Cu is formed on the piezoelectric body 29.
[0089]
Next, as shown in FIG. 14D, a diaphragm 26 made of Cr is formed on the common electrode 27 by sputtering or vapor deposition.
[0090]
Next, as shown in FIG. 15A, the head body 17 in which the pressure chamber 19 is formed on the vibration plate 26 is electrodeposited.
[0091]
Next, as shown in FIG. 15B, the MgO substrate 47 is removed by etching or the like.
[0092]
Next, as shown in FIG. 15C, the upper electrode 49 corresponding to the part where the individual electrode 33 and the individual electrode wiring 34 are formed is individualized by etching or the like, so that the individual electrode 33 and the individual electrode wiring 34 are formed. Form.
[0093]
Finally, as shown in FIG. 15D, the piezoelectric body 29 located at a portion corresponding to the individual electrode 33 and the individual electrode wiring 34 is individualized by wet etching.
[0094]
According to the present embodiment, even when Pt of the material of the upper electrode 49 is diffused into the surface layer of the piezoelectric body 29 on the individual electrode 33 side when the piezoelectric body 29 is formed on the upper electrode 49, the individual electrode 33 and the individual Since the piezoelectric body 29 located in a portion other than the electrode wiring 34 has been removed, when the voltage is applied to both the electrodes 27 and 33 or the voltage applied to each individual electrode 33 is individually controlled, When a potential difference occurs between the matching individual electrodes 33 or between the individual electrode wirings 34, Pt does not precipitate between the individual electrode wirings 34 on the upper surface of the piezoelectric body 29. In addition, since the piezoelectric body 29 exists only at a position corresponding to each individual electrode 33 and each individual electrode wiring 34, the entire area of the piezoelectric body 29 is uniformly displaced when a voltage is applied, and there is no portion that is not displaced. Therefore, cracks are less likely to occur in the piezoelectric body 29 when a voltage is applied. Therefore, migration between the individual electrode wirings 34 can be prevented, and a decrease in reliability due to generation of cracks in the piezoelectric body 29 can be prevented.
[0095]
According to the present embodiment, the inkjet head 1 is manufactured by the transfer method, but may be manufactured by the direct method.
[0096]
Further, a piezoelectric body 29 is formed on a lower piezoelectric body formed on the common electrode 27, and an upper piezoelectric body formed on the lower piezoelectric body and having a composition ratio of Pb lower than the composition ratio of Pb of the lower piezoelectric body. May be used.
[0097]
(Embodiment 5)
The piezoelectric actuator according to the present embodiment has a structure in which a piezoelectric body is formed on the individual electrode and the individual electrode wiring after the upper electrode is individualized into the individual electrode and the individual electrode wiring. It has almost the same configuration. Hereinafter, a configuration different from the third embodiment will be described.
[0098]
As shown in FIG. 16, the piezoelectric actuator 21 includes a diaphragm 26 made of 2 μm Cr, a common electrode 27 formed of 5.5 μm thick Cu on the diaphragm 26, and a common electrode 27 formed on the common electrode 27. 3 μm thick Pb (Zr, Ti) O ₃ , A 0.1 μm thick individual electrode 33 made of Pt formed on the piezoelectric body 29, and a 0.1 μm thick formed on the piezoelectric body 29 and connected to the individual electrode 33. And an individual electrode wiring 34 made of Pt.
[0099]
An electrode recess (not shown) and a wiring recess 31 are formed on the upper surface of the piezoelectric body 29. The individual electrode 33 is provided in the electrode recess, and the individual electrode wiring 34 is provided in the wiring recess 31. The upper surface of the piezoelectric body 29, the upper surface of the individual electrode 33, and the upper surface of the individual electrode wiring 34 are on the same plane.
[0100]
The periphery of the individual electrode 33 and the individual electrode wiring 34 in the piezoelectric body 29 constitutes an electrode material diffusion layer 30.
[0101]
(Method of manufacturing inkjet head)
Next, a method for manufacturing the inkjet head 1 will be described with reference to FIGS.
[0102]
First, as shown in FIG. 17A, an upper electrode 49 made of Pt is formed on an MgO substrate 47 by sputtering or vapor deposition.
[0103]
Next, as shown in FIG. 17B, the individual electrodes 33 and the individual electrode wirings 34 are formed by individualizing the upper electrodes 49 corresponding to the portions where the individual electrodes 33 and the individual electrode wirings 34 are formed by etching or the like. Form.
[0104]
Next, as shown in FIG. 17C, Pb (Zr, Ti) O is formed on the individual electrode 33, the individual electrode wiring 34, and the MgO substrate 47 by sputtering or vapor deposition. ₃ Is formed. At this time, Pt, which is a material of the individual electrode 33 and the individual electrode wiring 34, diffuses around the individual electrode 33 and the individual electrode wiring 34 in the piezoelectric body 29. This peripheral portion forms the electrode material diffusion layer 30.
[0105]
Next, as shown in FIG. 17D, a common electrode 27 made of Cu is formed on the piezoelectric body 29.
[0106]
Next, as shown in FIG. 18A, a diaphragm 26 made of Cr is formed on the common electrode 27 by sputtering, vapor deposition, or the like.
[0107]
Next, as shown in FIG. 18B, the head main body 17 in which the pressure chamber 19 is formed on the vibration plate 26 is electrodeposited.
[0108]
Finally, as shown in FIG. 18C, the MgO substrate 47 is removed by etching or the like.
[0109]
According to this embodiment, after the individual electrode 33 and the individual electrode wiring 34 are formed by individualizing the upper electrode 49, the piezoelectric body 29 is formed on the individual electrode 33, the individual electrode wiring 34, and the MgO substrate 47. Therefore, Pt, which is a material of the individual electrode 33 and the individual electrode wiring 34, is diffused only in the peripheral portion of the piezoelectric body 29 around the individual electrode 33 and the individual electrode wiring 34. Therefore, even if a voltage is applied to both electrodes 27 and 33, or a voltage applied to each individual electrode 33 is individually controlled, a potential difference is generated between adjacent individual electrodes 33 or between individual electrode wires 34. Also, Pt does not precipitate between the individual electrode wires 34 on the upper surface of the piezoelectric body 29. Therefore, migration between the individual electrode wirings 34 can be prevented.
[0110]
The piezoelectric body 29 is composed of a lower piezoelectric body formed on the common electrode 27 and an upper piezoelectric body which is formed on the lower piezoelectric body and whose Pb composition ratio is lower than the Pb composition ratio of the lower piezoelectric body. You may comprise.
[0111]
Further, according to the above embodiments, the diaphragm 26 and the common electrode 27 are provided separately, but the common electrode 27 may also serve as the diaphragm.
[0112]
According to the above embodiments, the piezoelectric body 29 is made of Pb (Zr, Ti) O ₃ However, except for the first and second embodiments, any material having piezoelectric characteristics may be used. Further, a piezoelectric body having a thickness different from that of each of the above embodiments may be used.
[0113]
Further, the common electrode 27, the individual electrode 33, the head main body 17 and the like may be made of a material and a thickness different from those of the above embodiments.
[0114]
Further, according to each of the above embodiments, the common electrode 27 is formed on the head body 17, but the individual electrode 33 may be formed on the head body 17. At this time, the common electrode 27 is formed on the piezoelectric body 29.
[0115]
Further, according to each of the above embodiments, the piezoelectric actuator 21 is used for the ink jet head 1, but the invention is not limited to this, and the piezoelectric actuator 21 may be used for other mechanical devices.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus according to an embodiment.
FIG. 2 is a perspective view showing a part of the inkjet head according to the embodiment in a cutaway manner.
FIG. 3 is a plan view of the inkjet head according to the embodiment.
FIG. 4 is a sectional view taken along line AA of FIG. 3;
FIGS. 5A to 5D are a part of a manufacturing process of the ink jet head according to the first embodiment.
FIGS. 6A to 6D are a part of a manufacturing process of the inkjet head according to the first embodiment.
FIG. 7 is a sectional view of an inkjet head according to a second embodiment.
FIGS. 8A to 8E are a part of a manufacturing process of the inkjet head according to the second embodiment.
FIGS. 9A to 9D are a part of a manufacturing process of the inkjet head according to the second embodiment.
FIG. 10 is a sectional view of an inkjet head according to a third embodiment.
FIGS. 11A to 11D are a part of a process of manufacturing an inkjet head according to a third embodiment.
12A to 12D are a part of a manufacturing process of the inkjet head according to the third embodiment.
FIG. 13 is a sectional view of an ink jet head according to a fourth embodiment.
14A to 14D are a part of a manufacturing process of the inkjet head according to the fourth embodiment.
FIGS. 15A to 15D are a part of a manufacturing process of the inkjet head according to the fourth embodiment.
FIG. 16 is a sectional view of an inkjet head according to a fifth embodiment.
FIGS. 17A to 17D are a part of a manufacturing process of the ink jet head according to the fifth embodiment.
FIGS. 18A to 18C are a part of a manufacturing process of the ink jet head according to the fifth embodiment.
[Explanation of symbols]
1 inkjet head
17 Head body
27 Common electrode (first electrode layer)
29 Piezoelectric body
29a Lower piezoelectric body
29b Upper piezoelectric body
30 Diffusion layer of electrode material
33 Individual electrode (second electrode layer)
34 Wiring for individual electrode (second electrode layer)

Claims (15)

A piezoelectric layer comprising: a first electrode layer; a piezoelectric layer formed on the first electrode layer; and a second electrode layer formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the first electrode layer. An actuator,
The piezoelectric layer is formed on the first electrode layer, the first electrode layer side piezoelectric layer containing Pb, and the first electrode layer side piezoelectric layer is formed on the first electrode layer side piezoelectric layer. And a second electrode layer-side piezoelectric layer lower than the first electrode layer-side piezoelectric layer. The first electrode layer has a common electrode layer,
The second electrode layer has a plurality of individualized individual electrodes and a plurality of individual electrode wirings connecting the individual electrodes and a plurality of voltage input terminals provided corresponding to the individual electrodes. Item 7. The piezoelectric actuator according to Item 1. A piezoelectric actuator comprising: a common electrode layer, a piezoelectric layer formed on the common electrode layer, and an individual electrode layer formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the common electrode layer. ,
The piezoelectric layer has a first piezoelectric layer formed on the common electrode layer, and a second piezoelectric layer formed on the first piezoelectric layer,
The individual electrode layer includes a plurality of individualized individual electrodes and a plurality of individual electrode wirings connecting the individual electrodes and a plurality of voltage input terminals provided corresponding to the individual electrodes. ,
A piezoelectric actuator in which the second piezoelectric layer is individualized so as to be located at a portion corresponding to each of the individual electrodes and each of the individual electrode wires. A piezoelectric actuator comprising: a common electrode layer, a piezoelectric layer formed on the common electrode layer, and an individual electrode layer formed on the piezoelectric layer and applying a voltage to the piezoelectric layer together with the common electrode layer. ,
The individual electrode layer includes a plurality of individualized individual electrodes and a plurality of individual electrode wirings connecting the individual electrodes and a plurality of voltage input terminals provided corresponding to the individual electrodes. ,
A piezoelectric actuator, wherein the piezoelectric layer is individualized so as to be located at a portion corresponding to each of the individual electrodes and the individual electrode wiring. An inkjet head comprising the piezoelectric actuator according to claim 1. A piezoelectric actuator according to claim 2,
An ink flow path forming member formed on the first electrode layer side surface or the second electrode layer side surface of the piezoelectric actuator and formed with a plurality of nozzles and a plurality of pressure chambers communicating with the nozzles; With
The inkjet head, wherein each of the individual electrodes is located at a portion corresponding to each of the pressure chambers. A piezoelectric actuator according to claim 3,
An ink flow path forming member formed on the common electrode layer side surface or the individual electrode layer side surface of the piezoelectric actuator and formed with a plurality of nozzles and a plurality of pressure chambers communicating with the nozzles; ,
The inkjet head, wherein each of the individual electrodes is located at a portion corresponding to each of the pressure chambers. A piezoelectric actuator according to claim 4,
An ink flow path forming member formed on the common electrode layer side surface or the individual electrode layer side surface of the piezoelectric actuator and formed with a plurality of nozzles and a plurality of pressure chambers communicating with the nozzles; ,
The inkjet head, wherein each of the individual electrodes is located at a portion corresponding to each of the pressure chambers. An inkjet recording apparatus comprising the inkjet head according to claim 5. Forming an individual electrode layer on the first substrate;
Forming an individual electrode layer-side piezoelectric layer containing Pb on the individual electrode layer;
Forming a common electrode layer-side piezoelectric layer containing Pb and having a higher composition ratio of Pb than the individual electrode layer-side piezoelectric layer on the individual electrode layer-side piezoelectric layer;
Forming a common electrode layer on the common electrode layer side piezoelectric layer,
Fixing a second substrate on the common electrode layer;
Removing the first substrate;
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
A method for manufacturing a piezoelectric actuator comprising: Forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate,
Forming a common electrode layer-side piezoelectric layer containing Pb on the common electrode layer;
Forming, on the common electrode layer side piezoelectric layer, an individual electrode layer side piezoelectric layer containing Pb and having a composition ratio of Pb lower than the common electrode layer side piezoelectric layer,
Forming an individual electrode layer on the individual electrode layer side piezoelectric layer,
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
A method for manufacturing a piezoelectric actuator comprising: Forming an individual electrode layer on the first substrate;
Forming a piezoelectric layer on the individual electrode layer;
Forming a common electrode layer on the piezoelectric layer;
Fixing a second substrate on the common electrode layer;
Removing the first substrate;
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
Removing the surface layer on the individual electrode layer side of the piezoelectric layer located in a portion other than the portion corresponding to each individual electrode and each individual electrode wiring,
A method for manufacturing a piezoelectric actuator comprising: Forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate,
Forming a piezoelectric layer on the common electrode layer,
Forming an individual electrode layer on the piezoelectric layer;
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
Removing the surface layer on the individual electrode layer side of the piezoelectric layer located in a portion other than the portion corresponding to each individual electrode and each individual electrode wiring,
A method for manufacturing a piezoelectric actuator comprising: Forming an individual electrode layer on the first substrate;
Forming a piezoelectric layer on the individual electrode layer;
Forming a common electrode layer on the piezoelectric layer;
Fixing a second substrate on the common electrode layer;
Removing the first substrate;
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
Individualizing a portion of the piezoelectric layer corresponding to each individual electrode and each individual electrode wiring,
A method for manufacturing a piezoelectric actuator comprising: Forming a diaphragm on a substrate, and forming a common electrode layer on the diaphragm or forming a common electrode layer also serving as a diaphragm on the substrate,
Forming a piezoelectric layer on the common electrode layer,
Forming an individual electrode layer on the piezoelectric layer;
A step of individualizing the individual electrode layer into a plurality of individual electrodes and a plurality of individual electrode wirings,
Individualizing a portion of the piezoelectric layer corresponding to each individual electrode and each individual electrode wiring,
A method for manufacturing a piezoelectric actuator comprising:

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