JP2011044528A - Piezoelectric element, piezoelectric actuator, liquid injection head, and liquid injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable piezoelectric element, a piezoelectric actuator, a liquid injection head and a liquid injection device. <P>SOLUTION: The piezoelectric element 100 includes a substrate 10, a lower electrode 20 formed on the substrate 10, a piezoelectric layer 30 formed to cover a side face 34 and an upper surface 32 of the lower electrode 20, and an upper electrode 40 formed to cover the side face 34 and the upper surface 32 of the piezoelectric layer 30. The upper electrode 40 has a first region 40A and a second region 40B on the upper surface 32 of the piezoelectric layer 30. The first region 40A includes at least part of a region overlapping the lower electrode 20 in a plan view. The second region 40B is a region other than the first region 40A, and the first region 40A is thinner than the second region 40B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a piezoelectric element, a piezoelectric actuator, a liquid ejecting head, and a liquid ejecting apparatus.

  The piezoelectric element includes a structure in which a piezoelectric body is sandwiched between two electrodes. Since the piezoelectric element includes such a structure, an electric field can be applied to the piezoelectric body to cause deformation such as expansion and contraction.

  Piezoelectric elements are also used in piezoelectric actuators such as liquid jet heads. The performance of the piezoelectric element may deteriorate due to deterioration of the piezoelectric body. It is known that when a piezoelectric body comes into contact with moisture, for example, an increase in leakage current generated between two electrodes is generated, and the reliability of the piezoelectric element is lowered.

  As a method for suppressing the contact of the piezoelectric body with moisture, the piezoelectric body is covered with a barrier film. As an example of this, in JP-A-2005-088441 (Patent Document 1), a piezoelectric body is covered with an electrode, and the electrode also serves as a barrier film, thereby suppressing contact between the piezoelectric body and moisture. There is a disclosure of a liquid jet head.

Japanese Patent Laying-Open No. 2005-088441

  One of the objects according to some embodiments of the present invention is to provide a highly reliable piezoelectric element.

  One of the objects according to some embodiments of the present invention is to provide a piezoelectric actuator including the piezoelectric element.

  An object of some embodiments of the present invention is to provide a liquid jet head including the piezoelectric actuator.

  An object of some embodiments of the present invention is to provide a liquid ejecting apparatus including the liquid ejecting head.

(1) A piezoelectric element according to one aspect of the present invention is:
A substrate,
A lower electrode formed above the substrate;
A piezoelectric layer formed to cover a side surface and an upper surface of the lower electrode;
An upper electrode formed to cover a side surface and an upper surface of the piezoelectric layer;
Including
The upper electrode has a first region and a second region on the upper surface of the piezoelectric layer,
The first region includes at least a part of a region overlapping the lower electrode in plan view,
The second region is a region other than the first region,
The first region has a smaller thickness than the second region.

  In the piezoelectric element according to one aspect of the present invention, the thickness of the upper electrode in the first region is smaller than the thickness of the upper electrode in the second region. As a result, the mechanical operation (deformation, etc.) of the piezoelectric element can be further restrained, and a highly reliable piezoelectric element can be obtained.

(2) In the piezoelectric element according to one aspect of the present invention,
The upper electrode has a first upper electrode and a second upper electrode,
The first upper electrode is formed on an upper surface of the piezoelectric layer,
The second upper electrode may be formed on a side surface of the piezoelectric layer and the second region, and may be formed on an upper surface of the first upper electrode in the second region.

  In the piezoelectric element according to one aspect of the present invention, the first upper electrode can serve as an etching stopper when the second upper electrode formed in the first region is removed. Therefore, since the first upper electrode is difficult to be etched, the reliability of the piezoelectric element can be further improved.

(3) In the piezoelectric element according to one aspect of the present invention,
Furthermore, it has an intermediate layer,
The intermediate layer may be formed in the first region and the second region, and may be located between the first upper electrode and the second upper electrode.

  In the piezoelectric element according to one aspect of the present invention, the intermediate layer can serve as an etching stopper when the second upper electrode formed in the first region is removed. Therefore, since the first upper electrode is not etched, a highly reliable piezoelectric element can be obtained.

(4) In the piezoelectric element according to one aspect of the present invention,
Furthermore, it has an intermediate layer,
The intermediate layer may be formed in the second region and positioned between the first upper electrode and the second upper electrode.

  In the piezoelectric element according to one aspect of the present invention, no intermediate layer is formed in the first region. As a result, the mechanical operation (deformation, etc.) of the piezoelectric element can be further restrained, and a highly reliable piezoelectric element can be obtained.

(5) In the piezoelectric element according to one aspect of the present invention,
Further, the intermediate layer may be formed on a side surface of the piezoelectric layer, and may be positioned below the second upper electrode on the side surface of the piezoelectric layer.

  In the piezoelectric element according to one aspect of the present invention, the second upper electrode is not in contact with the piezoelectric element. Therefore, since the second upper electrode is not easily oxidized, a highly reliable piezoelectric element can be obtained.

(6) A piezoelectric actuator according to one aspect of the present invention is:
Including the piezoelectric element described above,
The substrate is deformed by the operation of the piezoelectric layer.

  Since the piezoelectric actuator according to one aspect of the present invention includes the piezoelectric element, it can have high reliability.

(7) A liquid jet head according to one aspect of the present invention includes:
The above piezoelectric actuator;
A pressure chamber in communication with the nozzle hole, the volume of which is changed by the operation of the piezoelectric actuator;
including.

  Since the liquid ejecting head according to one aspect of the present invention includes the piezoelectric actuator, the liquid ejecting head can have high reliability.

(8) A liquid ejecting apparatus according to one aspect of the present invention includes:
The liquid ejecting head is included.

  Since the liquid ejecting apparatus according to one aspect of the present invention includes the liquid ejecting head, the liquid ejecting apparatus can have high reliability.

1 is a cross-sectional view schematically showing a piezoelectric element 100 according to a first embodiment. Sectional drawing which shows typically the piezoelectric element 110 which concerns on 2nd Embodiment. Sectional drawing which shows typically the piezoelectric element 120 which concerns on 3rd Embodiment. Sectional drawing which shows typically the piezoelectric element 130 which concerns on 4th Embodiment. Sectional drawing which shows typically the piezoelectric element 140 which concerns on 5th Embodiment. Sectional drawing which shows typically the piezoelectric element 150 which concerns on 6th Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 100 which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 100 which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 100 which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 100 which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 100 which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 110 which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 110 which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 110 which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 110 which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 120 which concerns on 3rd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 120 which concerns on 3rd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 120 which concerns on 3rd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 120 which concerns on 3rd Embodiment. Sectional drawing which shows typically the manufacturing process of the piezoelectric element 140 which concerns on 5th Embodiment. FIG. 10 is a cross-sectional view schematically showing a liquid ejecting head according to a seventh embodiment. FIG. 10 is an exploded perspective view schematically illustrating a liquid ejecting head 400 according to a seventh embodiment. FIG. 10 is a perspective view schematically showing a liquid ejecting apparatus 500 according to an eighth embodiment.

  Hereinafter, although embodiment of this invention is described, this invention is not restrict | limited to these.

1. 1. First Embodiment 1.1 Piezoelectric Element FIG. 1 is a cross-sectional view schematically showing a piezoelectric element 100 according to a first embodiment. As shown in FIG. 1, the piezoelectric element 100 according to the present embodiment includes a substrate 10, a lower electrode 20, a piezoelectric layer 30, and an upper electrode 40.

  The substrate 10 can be a flat plate formed of, for example, a conductor, a semiconductor, or an insulator. The substrate 10 may be a single layer or a structure in which a plurality of layers are stacked. Further, the internal structure of the substrate 10 is not limited as long as the upper surface is planar, and for example, a structure in which a space or the like is formed may be used. For example, in the case where a pressure chamber or the like is formed below the substrate 10 as in a liquid jet head (see FIG. 21) described later, a plurality of configurations formed below the substrate 10 are integrated together. One substrate 10 may be considered.

  The substrate 10 may be, for example, a diaphragm that is flexible and can be deformed (bent) by the operation of the piezoelectric layer 30. In this case, the piezoelectric element 100 is a piezoelectric actuator 102 including a diaphragm, a lower electrode 20, a piezoelectric layer 30, and an upper electrode 40. Here, that the substrate 10 has flexibility indicates that the substrate 10 can bend. When the substrate 10 is a vibration plate, the deflection of the substrate 10 is such that, for example, when the piezoelectric actuator 102 is used for a liquid ejecting head, the volume of the pressure chamber can be changed to the same level as the volume of liquid to be ejected.

  When the substrate 10 is a diaphragm, examples of the material of the substrate 10 include inorganic oxides such as zirconium oxide, silicon nitride, and silicon oxide, and alloys such as stainless steel. Even in this case, the substrate 10 may have a laminated structure of two or more kinds of the exemplified substances.

  In the present embodiment, the case where the substrate 10 is a diaphragm and is formed of zirconium oxide will be exemplified below. Therefore, the piezoelectric element 100 is substantially the same as the piezoelectric actuator 102 having a vibration plate that has flexibility and can be deformed (bent) by the operation of the piezoelectric layer 30. Therefore, in the following description, the piezoelectric element 100 and the piezoelectric actuator 102 can be read each other.

  The thickness of the substrate 10 (diaphragm) can be selected depending on the elastic modulus of the material used. The thickness of the substrate 10 can be, for example, 200 nm or more and 2000 nm or less. When the thickness of the substrate 10 is less than 200 nm, it may be difficult to extract mechanical output such as vibration, and when it is thicker than 2000 nm, vibration or the like may not occur.

The lower electrode 20 is formed above the substrate 10. Examples of the material of the lower electrode 20 include various metals such as nickel, iridium, and platinum, conductive oxides thereof (for example, iridium oxide), strontium and ruthenium composite oxide (SrRuO _x : SRO), lanthanum, and the like. An example is a composite oxide of nickel (LaNiO _x : LNO).

  The lower electrode 20 may have a single-layer structure of the exemplified materials or a structure in which a plurality of materials are stacked. For example, an adhesion layer or the like may be formed between the lower electrode 20 and the substrate 10. Examples of the adhesion layer in this case include a titanium layer.

  The thickness of the lower electrode 20 can be, for example, 50 nm or more and 300 nm or less. A function of the lower electrode 20 is to become one electrode (a lower electrode formed under the piezoelectric layer 30) for applying a voltage to the piezoelectric layer 30.

  The piezoelectric layer 30 is formed so as to cover the side surface and the upper surface of the lower electrode 20. In the example of FIG. 1, the piezoelectric layer 30 is formed to cover the upper surface and side surfaces of the lower electrode 20 and the upper surface of the substrate 10. Another layer may be formed between the piezoelectric layer 30 and the lower electrode 20. Examples of other layers in this case include an orientation control layer (for example, a titanium layer) for controlling the crystal orientation of the piezoelectric layer 30.

  The thickness of the piezoelectric layer 30 can be, for example, not less than 300 nm and not more than 3000 nm. If the thickness of the piezoelectric layer 30 is out of the above range, the expansion and contraction necessary for deforming the substrate 10 may not be obtained.

  The piezoelectric layer 30 has an upper surface 32 and a side surface 34 continuous with the upper surface 32. In the illustrated example, the upper surface 32 of the piezoelectric layer 30 is a flat surface and is parallel to the upper surface of the substrate 10. The side surface 34 of the piezoelectric layer 30 may be constituted by one surface or a plurality of surfaces. The side surface 34 of the piezoelectric layer 30 may be configured to include a curved surface.

  The piezoelectric layer 30 is formed of a piezoelectric material. Therefore, the piezoelectric layer 30 can be deformed by applying an electric field by the lower electrode 20 and the upper electrode 40. By this deformation, the substrate 10 can bend or vibrate.

As a material of the piezoelectric layer 30, a perovskite oxide represented by a general formula ABO ₃ can be used. Specific examples of such a material include lead zirconate titanate (Pb (Zr, Ti) O ₃ ) (hereinafter sometimes abbreviated as “PZT”), lead zirconate titanate niobate (Pb ( Zr, Ti, Nb) O ₃ ) (hereinafter sometimes abbreviated as “PZTN”), barium titanate (BaTiO ₃ ), potassium sodium niobate ((K, Na) NbO ₃ ) and the like. .

  The upper electrode 40 is formed so as to cover the upper surface 32 and the side surface 34 of the piezoelectric layer 30. In the example of FIG. 1, the upper electrode 40 is formed so as to cover the upper surface of the substrate 10 and the upper surface 32 and the side surface 34 of the piezoelectric layer 30.

  The upper electrode 40 has a first region 40A and a second region 40B on the upper surface 32 of the piezoelectric layer 30. 40 A of 1st area | regions include at least one part of the area | region which overlaps with the lower electrode 20 in planar view. The second area 40B is an area other than the first area 40A.

  In the example of FIG. 1, the first region 40A indicates a region overlapping with the lower electrode 20 in plan view. In the example of FIG. 1, the second region 40B indicates a region excluding a region overlapping the lower electrode 20 in a plan view, that is, a region other than the first region 40A.

  In the upper electrode 40, the first region 40A is smaller in thickness than the second region 40B. In the example of FIG. 1, the thickness of the upper electrode 40 on the upper surface 32 of the piezoelectric layer 30 is formed so that the first region 40A is thinner than the second region 40B. By forming the first region 40A thinner than the second region 40B, it is possible to further restrain the mechanical operation (deformation, etc.) of the piezoelectric layer 30 by the upper electrode 40.

  The function of the upper electrode 40 is to pair with the lower electrode 20 and to be one electrode of the piezoelectric element 100. Further, as a function of the upper electrode 40, it is possible to suppress contact between the piezoelectric material of the piezoelectric layer 30 and moisture or the like from the outside. That is, the upper electrode 40 has a barrier property that hardly allows moisture to pass therethrough. Therefore, deterioration of the piezoelectric material of the piezoelectric layer 30 covered with the upper electrode 40 due to moisture or the like is suppressed.

  The thickness of the upper electrode 40 is not limited as long as it has a barrier property and does not adversely affect the operation of the piezoelectric element 100. The thickness of the upper electrode 40 can be 10 nm or more and 200 nm or less, for example. If the thickness of the upper electrode 50 is less than 10 nm, the electrical resistance may increase, the barrier property may be insufficient, and pinholes may be generated. If the thickness is greater than 200 nm, deformation of the piezoelectric element 100 may be hindered. There is.

  In particular, the thickness of the upper electrode 40 in the first region 40A can be 10 nm or more and 50 nm or less. By limiting the thickness of the first region 40A within the above range, the mechanical operation (deformation, etc.) of the piezoelectric element 100 can be further restrained. Therefore, the deformation of the piezoelectric element 100 can be further improved, and a highly reliable piezoelectric element can be obtained.

  The material of the upper electrode 40 is not particularly limited as long as it has barrier properties and conductivity. Examples of the material of the upper electrode 40 include various metals such as nickel, iridium, and platinum, their conductive oxides (for example, iridium oxide), SRO, LNO, and the like. Further, the upper electrode 40 may be a single layer or a structure in which a plurality of layers are stacked.

  The upper electrode 40 can be formed by a method such as vapor deposition or sputtering. The upper electrode 40 formed by such a method may generate a residual stress inside the film during the film formation. The stress remaining inside tends to be concentrated on the portion where the upper electrode 40 is bent in the thickness direction. That is, the residual stress concentrates on a bent portion that is a boundary portion between the upper surface 32 and the side surface 34 in the piezoelectric layer 30. The upper electrode 40 formed in the bent portion is more likely to break such as a crack than other portions. Therefore, in the upper electrode 40, cracks and the like can be prevented by forming the second region 40B having a thickness larger than that of the first region 40A in the bent portion.

  In the piezoelectric element 100 according to this embodiment, the thickness of the upper electrode 40 on the upper surface 32 of the piezoelectric layer 30 is smaller in the first region 40A than in the second region 40B. Therefore, the restraint of the mechanical operation (deformation and the like) of the piezoelectric element 100 can be further reduced. Therefore, the deformation of the piezoelectric element 100 can be further improved, and the highly reliable piezoelectric element 100 can be obtained.

  In addition, 2nd Embodiment thru | or 8th Embodiment mentioned later can have the effect similar to the above-mentioned 1st Embodiment, The description is abbreviate | omitted about the same effect.

1.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing a piezoelectric element, a method for manufacturing the piezoelectric element 100 of the first embodiment described above will be exemplified and described with reference to the drawings. 7 to 11 are cross-sectional views schematically showing the manufacturing process of the piezoelectric element 100.

  First, as shown in FIG. 7, the lower electrode 20 is formed on the substrate 10. In the example of FIG. 7, a substrate 10 in which a zirconia layer 14 is formed on a silicon substrate 12 is used. The lower electrode 20 can be formed by, for example, a sputtering method, a plating method, a vacuum evaporation method, or the like. More specifically, the lower electrode 20 can be formed by forming and patterning a lower electrode (not shown) on the entire surface of the substrate 10.

  Next, as shown in FIG. 8, a piezoelectric layer 30 a is formed on the entire upper surface of the substrate 10 so as to cover the lower electrode 20. Thereby, the piezoelectric layer 30a is formed on the side and the upper side of the lower electrode 20. The piezoelectric layer 30a can be formed by, for example, a sol-gel method, a CVD (Chemical Vapor Deposition) method, a MOD (Metal Organic Deposition) method, a sputtering method, a laser ablation method, or the like. Here, when the material of the piezoelectric layer 30a is, for example, PZT, the piezoelectric layer 30a can be crystallized by performing annealing at about 700 ° C. in an oxygen atmosphere. The crystallization may be performed after patterning the piezoelectric layer 30a.

  Next, a first patterning process is performed. The first patterning step can be performed as follows, for example. First, a resist having a desired shape is formed on the upper surface of the piezoelectric layer 30a (not shown). Next, the piezoelectric layer 30a is etched using the resist as a mask to form the piezoelectric layer 30. In this way, a laminated structure of the lower electrode 20 and the piezoelectric layer 30 is formed as shown in FIG.

Etching in the first patterning step can be performed by dry etching using a high-density plasma apparatus such as ICP (Inductively Coupled Plasma), for example. In a high-density plasma apparatus (dry etching apparatus), good etching can be performed when the pressure is set to 1.0 Pa or less. As an etching gas when PZT is used for the piezoelectric layer 30a, for example, a mixed gas of a chlorine-based gas and a chlorofluorocarbon-based gas can be used. Examples of the chlorine-based gas include Cl ₂ and BCl ₃ . Examples of the fluorocarbon gas include C ₄ F ₈ , CF _{4, and the} like.

  Next, as shown in FIG. 10, the upper electrode 40 a is formed so as to cover the upper surface of the substrate 10 and the upper surface 32 and the side surface 34 of the piezoelectric layer 30. The upper electrode 40a can be formed by, for example, a sputtering method, a plating method, a vacuum evaporation method, or the like.

  Next, a second patterning process is performed. The second patterning step can be performed as follows, for example. First, a resist having a predetermined shape is formed in a region other than the first region 40A on the upper surface of the upper electrode 40a (not shown). Next, using the resist as a mask, as shown in FIG. 11, the first region 40A is etched to a desired thickness (for example, not less than 10 nm and not more than 50 nm) to form the upper electrode 40. Through the second patterning step, the thickness of the upper electrode 40 on the upper surface 32 of the piezoelectric layer 30 is formed so that the first region 40A is thinner than the second region 40B.

  The etching in the second patterning step can be performed by the same method as the etching in the first patterning step. For example, as an etching gas when iridium is used for the upper electrode 40a, for example, a mixed gas of chlorine gas and argon gas can be used.

  Next, if necessary, the upper electrode 40 may be patterned to form a wiring layer of the upper electrode (not shown).

  Through the above steps, the piezoelectric element 100 can be manufactured. According to the method for manufacturing the piezoelectric element 100 according to the present embodiment, the mechanical operation (deformation, etc.) of the piezoelectric element 100 can be restrained to a smaller extent, and the highly reliable piezoelectric element 100 can be easily manufactured. it can.

2. 2. Second Embodiment 2.1 Piezoelectric Element Next, a piezoelectric element 110 according to a second embodiment will be described with reference to the drawings. FIG. 2 is a cross-sectional view schematically showing the piezoelectric element 110 according to the second embodiment, and corresponds to FIG. Hereinafter, in the piezoelectric element 110 according to the second embodiment, members having the same functions as those of the constituent members of the piezoelectric element 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piezoelectric element 110 according to the second embodiment is different from the piezoelectric element 100 according to the first embodiment in that the upper electrode 40 includes a first upper electrode 42 and a second upper electrode 44. In other respects, the piezoelectric element 110 according to the second embodiment is the same as the piezoelectric element 100 according to the first embodiment.

  As shown in FIG. 2, the upper electrode 40 can include a first upper electrode 42 and a second upper electrode 44. The first upper electrode 42 can be formed on the upper surface of the piezoelectric layer 30. In the example of FIG. 2, the first upper electrode 42 is formed so as to cover the upper surface 32 of the piezoelectric layer 30.

  The second upper electrode 44 may be formed on the side surface 34 of the piezoelectric layer 30 and the second region 40B, and may be formed on the upper surface of the first upper electrode 42 in the second region 40B. In the example of FIG. 2, the second upper electrode 44 is formed on the upper surface of the substrate 10, the side surface 34 of the piezoelectric layer 30, and the second region 40B. Further, in the example of FIG. 2, the second upper electrode 44 is formed on the upper surface of the first upper electrode 42 in the second region 40B.

  As shown in FIG. 2, a first upper electrode 42 is formed in the first region 40A. On the other hand, a first upper electrode 42 and a second upper electrode 44 are formed in the second region 40B. Therefore, the upper electrode 40 is formed such that the first region 40A is thinner than the second region 40B on the upper surface 32 of the piezoelectric layer 30. For this reason, it is possible to further restrain the mechanical operation (deformation, etc.) of the piezoelectric layer 30 by the upper electrode 40.

  The material of the upper electrode 40 exemplified in the first embodiment can be used for the first upper electrode 42 and the second upper electrode 44. The first upper electrode 42 and the second upper electrode 44 may be made of the same material or different materials. When a different material is used, the first upper electrode 42 can be used as an etching stopper layer by using an etching condition that can selectively remove only the second upper electrode, and the second upper electrode formed in the first region 40A. 44 can be easily removed.

  When the first upper electrode 42 is used as an etching stopper, the etching can be stopped when the upper surface of the first upper electrode 42 is exposed. Therefore, the upper surface of the first region 40A is hardly etched. Therefore, it is easy to process the thickness of the first region 40A to be constant, and it is easy to manufacture a piezoelectric element having uniform characteristics.

  Further, as described above, the upper surface of the first region 40A is hardly etched. Therefore, the upper surface of the first region 40A in the second embodiment can have a flat surface compared to the upper surface of the first region 40A in the first embodiment.

2.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing the piezoelectric element, a method for manufacturing the piezoelectric element 110 according to the second embodiment described above will be exemplified and described with reference to the drawings. 12 to 15 are cross-sectional views schematically showing the manufacturing process of the piezoelectric element 110. Hereinafter, in the method for manufacturing the piezoelectric element 110 according to the second embodiment, members having the same functions as those of the constituent members in the method for manufacturing the piezoelectric element 100 according to the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted. Description is omitted.

  The method for manufacturing the piezoelectric element 110 according to the second embodiment differs from the method for manufacturing the piezoelectric element 100 according to the first embodiment in the process of forming the upper electrode 40. In other respects, the method for manufacturing the piezoelectric element 110 according to the second embodiment is the same as the method for manufacturing the piezoelectric element 100 according to the first embodiment.

  As shown in FIG. 12, the first upper electrode 42a is formed on the entire upper surface of the piezoelectric layer 30a so as to cover the piezoelectric layer 30a. As a method for forming the first upper electrode 42a, the same method as the upper electrode 40a in the first embodiment described above can be used.

Next, a first patterning process is performed. In the first patterning step, as shown in FIG. 13, the first upper electrode 42a and the piezoelectric layer 30a are etched to form a laminated structure of the lower electrode 20, the piezoelectric layer 30, and the first upper electrode 42. For the etching in the first patterning step, the same method as in the first patterning step in the first embodiment described above can be used. For example, a mixed gas of chlorine gas and argon gas can be used as an etching gas when iridium is used for the first upper electrode 42a. In addition, as an etching gas when PZT is used for the piezoelectric layer 30a, a mixed gas of a chlorine-based gas and a chlorofluorocarbon-based gas can be used. Examples of the chlorine-based gas include Cl ₂ and BCl ₃ . Examples of the fluorocarbon gas include C ₄ F ₈ , CF _{4, and the} like.

  The upper surface of the piezoelectric layer 30a is covered with the first upper electrode 42a. Therefore, the upper surface of the piezoelectric layer 30a is not easily damaged by the first patterning process (for example, resist coating or resist peeling), and a highly reliable piezoelectric element can be formed.

  Next, as shown in FIG. 14, the second upper electrode 44 a is formed so as to cover the upper surface of the substrate 10, the side surface 34 of the piezoelectric layer 30, and the upper surface of the first upper electrode 42. As a method of forming the second upper electrode 44a, the same method as that of the upper electrode 40a in the first embodiment described above can be used.

  Next, a second patterning process is performed. In the second patterning step, as shown in FIG. 15, the second upper electrode 44a in the first region 40A is etched until the upper surface of the first upper electrode 42 is exposed. Thus, the upper electrode 40 composed of the first upper electrode 42 and the second upper electrode 44 is formed. By performing the second patterning step, only the first upper electrode 42 is formed in the first region 40A. On the other hand, a first upper electrode 42 and a second upper electrode 44 are formed in the second region 40B. Therefore, the upper electrode 40 is formed such that the first region 40A is thinner than the second region 40B on the upper surface 32 of the piezoelectric layer 30.

Etching in the second patterning step can be performed by the same method as in the second patterning step according to the first embodiment described above. For example, as an etching gas when tungsten is used for the second upper electrode 44a, a fluorocarbon gas can be used. Examples of the fluorocarbon gas include SF ₆ and CF ₄ .

  When different materials are used for the first upper electrode 42 and the second upper electrode 44, the etching selectivity can be used in the second patterning step. In the second patterning step, when an etching gas having a high selectivity with respect to the second upper electrode 44a is used, the etching can be easily terminated when the surface of the first upper electrode 42 is exposed. That is, the first upper electrode 42 functions as an etching stopper and is not easily etched in the second patterning step. Therefore, the first upper electrode 42 can reliably protect the upper surface 32 of the piezoelectric element from moisture and the like.

  If the first upper electrode 42 is used as an etching stopper, the etching can be stopped when the upper surface of the first upper electrode 42 is exposed. Therefore, the upper surface of the second region 40A is hardly etched. Therefore, the upper surface of the second region 40A in the second embodiment can have a more uniform and flat surface than the upper surface of the second region 40A in the first embodiment.

3. Third Embodiment 3.1 Piezoelectric Element Next, a piezoelectric element 120 according to a third embodiment will be described with reference to the drawings. FIG. 3 is a cross-sectional view schematically showing the piezoelectric element 120 according to the third embodiment, and corresponds to FIG. Hereinafter, in the piezoelectric element 120 according to the third embodiment, members having the same functions as the constituent members of the piezoelectric element 110 according to the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piezoelectric element 120 according to the third embodiment has the intermediate layer 50 between the first upper electrode 42 and the second upper electrode 44 on the upper surface of the piezoelectric layer 30, and thus the piezoelectric element according to the second embodiment. 110. In other respects, the piezoelectric element 120 according to the third embodiment is the same as the piezoelectric element 110 according to the second embodiment.

  The piezoelectric element 120 can have an intermediate layer 50. The intermediate layer 50 is formed in the first region 40 </ b> A and the second region 40 </ b> B, and can be located between the first upper electrode 42 and the second upper electrode 44. In the example of FIG. 3, the intermediate layer 50 is formed on the upper surface of the first upper electrode 42 in the first region 40A and the second region 40B. In the example of FIG. 3, the intermediate layer 50 is formed on the lower surface of the second upper electrode 44 in the second region 40 </ b> B.

Examples of the material of the intermediate layer 50 include various metals such as aluminum, titanium, nickel, iridium, and platinum, oxides thereof (for example, aluminum oxide, titanium oxide, iridium oxide, etc.), composite oxides of strontium and ruthenium ( Examples thereof include insulators such as SrRuO _x : SRO), a composite oxide of lanthanum and nickel (LaNiO _x : LNO), silicon oxide, and silicon nitride.

  The intermediate layer 50 may have a single layer structure of the exemplified materials or a structure in which a plurality of materials are stacked. The thickness of the intermediate layer 50 can be, for example, 10 nm or more and 300 nm or less.

  A function of the intermediate layer 50 is to become an etching stopper layer when the second upper electrode 44 is etched. Therefore, when the same material is used for the first upper electrode 42 and the second upper electrode 44, the second upper electrode 44 in the first region 40 </ b> A is selected by selecting a material to be an etching stopper layer for the intermediate layer 50. Can be easily removed.

3.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing a piezoelectric element, a method for manufacturing the piezoelectric element 120 of the above-described third embodiment will be exemplified and described with reference to the drawings. 16 to 19 are cross-sectional views schematically showing the manufacturing process of the piezoelectric element 120. Hereinafter, in the method for manufacturing the piezoelectric element 120 according to the third embodiment, members having the same functions as those of the constituent members in the method for manufacturing the piezoelectric element 110 according to the second embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted. Description is omitted.

  The manufacturing method of the piezoelectric element 120 according to the third embodiment is different from the manufacturing method of the piezoelectric element 110 according to the second embodiment in that an intermediate layer 50 forming step is added. In other respects, the method for manufacturing the piezoelectric element 120 according to the third embodiment is the same as the method for manufacturing the piezoelectric element 110 according to the second embodiment.

  As shown in FIG. 16, an intermediate layer 50a is formed on the entire upper surface of the first upper electrode 42a so as to cover the first upper electrode 42a. As a method for forming the intermediate layer 50a, a method similar to that for the first upper electrode 42a in the second embodiment described above can be used.

  Next, a first patterning process is performed. In the first patterning step, as shown in FIG. 17, the intermediate layer 50a, the first upper electrode 42a, and the piezoelectric layer 30a are etched, and the lower electrode 20, the piezoelectric layer 30, the first upper electrode 42, and the intermediate layer are etched. 50 laminated structures are formed.

For the etching in the first patterning step, for example, the same method as in the first patterning step in the second embodiment described above can be used. For example, chlorine gas can be used as an etching gas when titanium is used as the material of the intermediate layer 50a. In addition, as the etching gas when iridium is used for the first upper electrode 42a, a mixed gas of chlorine gas and argon gas can be used. In addition, as an etching gas when PZT is used for the piezoelectric layer 30a, a mixed gas of a chlorine-based gas and a chlorofluorocarbon-based gas can be used. Examples of the chlorine-based gas include Cl ₂ and BCl ₃ . Examples of the fluorocarbon gas include C ₄ F ₈ , CF _{4, and the} like.

  Next, as shown in FIG. 18, the second upper electrode 44a is formed so as to cover the upper surface of the substrate 10, the side surface 34 of the piezoelectric layer 30, and the intermediate layer 50a. As a method of forming the second upper electrode 44a, the same method as the second upper electrode 44a in the second embodiment described above can be used.

  Next, a second patterning process is performed. In the second patterning step, as shown in FIG. 19, the second upper electrode 44a in the first region 40A is etched until the upper surface of the intermediate layer 50 is exposed. Thus, the upper electrode 40 composed of the first upper electrode 42 and the second upper electrode 44 is formed. By performing the second patterning step, the first upper electrode 42 and the intermediate layer 50 are formed in the first region 40A. On the other hand, the first upper electrode 42, the intermediate layer 50, and the second upper electrode 44 are formed in the second region 40B. Therefore, the upper electrode 40 is formed such that the first region 40A is thinner than the second region 40B on the upper surface 32 of the piezoelectric layer 30.

  Etching in the second patterning step can be performed by the same method as in the second patterning step according to the first embodiment. For example, a mixed gas of chlorine gas and oxygen gas can be used as an etching gas when iridium is used for the second upper electrode 44a.

  When different materials are used for the intermediate layer 50 and the second upper electrode 44, the etching selectivity can be used in the second patterning step. As an example, a case where titanium is used for the intermediate layer 50 and iridium is used for the second upper electrode 44a will be described below. When a mixed gas of chlorine gas and oxygen gas is used as the etching gas for the second upper electrode 44a, the intermediate layer 50 is hardly etched due to the etching selectivity. For example, when the flow rate of oxygen gas is 40% or more, the etching rate of titanium used for the intermediate layer 50 becomes 1/10 or less of the etching rate of iridium used for the second upper electrode 44a. Therefore, the etching can be easily terminated when the surface of the intermediate layer 50 is exposed.

  Further, the intermediate layer 50 can function as an etching hard mask that prevents the etching of the first upper electrode 42 in the second patterning step.

  As described above, the second upper electrode 44 in the first region 40A can be easily removed by selecting a material to be the etching stopper layer for the intermediate layer 50. Therefore, in the method for manufacturing the piezoelectric element 120 according to this embodiment, the piezoelectric element 120 can be easily manufactured even if the same material is used for the first upper electrode 42 and the second upper electrode 44.

4). 4. Fourth Embodiment 4.1 Piezoelectric Element Next, a piezoelectric element 130 according to a fourth embodiment will be described with reference to the drawings. FIG. 4 is a cross-sectional view schematically showing the piezoelectric element 130 according to the fourth embodiment, and corresponds to FIG. Hereinafter, in the piezoelectric element 130 according to the fourth embodiment, members having the same functions as those of the constituent members of the piezoelectric element 120 according to the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piezoelectric element 130 according to the fourth embodiment is different from the piezoelectric element 120 according to the third embodiment in that the intermediate layer 50 is not provided in the first region 40A. In other respects, the piezoelectric element 130 according to the fourth embodiment is the same as the piezoelectric element 120 according to the third embodiment.

  The intermediate layer 50 is formed in the second region 40 </ b> B and can be positioned between the first upper electrode 42 and the second upper electrode 44. In the example of FIG. 4, the intermediate layer 50 is formed on the upper surface of the first upper electrode 42 and the lower surface of the second upper electrode 44 in the second region 40B.

  In the piezoelectric element 130 according to the fourth embodiment, the intermediate layer 50 is not formed in the first region 40A. Therefore, the piezoelectric element 130 according to the fourth embodiment suppresses the restraint of the mechanical operation (deformation, etc.) of the piezoelectric layer 30 in the first region 40A to be smaller than that of the piezoelectric element 120 according to the third embodiment. Can do.

4.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing a piezoelectric element, a method for manufacturing the piezoelectric element 130 of the above-described fourth embodiment will be exemplified and described. Hereinafter, in the method for manufacturing the piezoelectric element 130 according to the fourth embodiment, members having the same functions as those of the constituent members in the method for manufacturing the piezoelectric element 120 according to the third embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted. Description is omitted.

  The manufacturing method of the piezoelectric element 130 according to the fourth embodiment is different from the manufacturing method of the piezoelectric element 120 according to the third embodiment in that the patterning of the intermediate layer 50 is added in the second patterning step. In other respects, the method for manufacturing the piezoelectric element 130 according to the fourth embodiment is the same as the method for manufacturing the piezoelectric element 120 according to the third embodiment.

  In the method for manufacturing the piezoelectric element 130 according to the fourth embodiment, the second patterning step can be performed as follows. As shown in FIG. 19, first, the second upper electrode 44a in the first region 40A is etched until the upper surface of the intermediate layer 50a is exposed. Thus, the upper electrode 40 composed of the first upper electrode 42 and the second upper electrode 44 is formed.

  The etching of the second upper electrode 44 can be performed by the same method as the second patterning step in the third embodiment. For example, a mixed gas of chlorine gas and oxygen gas can be used as an etching gas when iridium is used for the second upper electrode 44a.

  Next, as shown in FIG. 4, the intermediate layer 50 a in the first region is etched until the upper surface of the first upper electrode 42 is exposed, whereby the piezoelectric element 130 is obtained.

  The etching of the intermediate layer 50a can be performed by the same method as the etching in the second patterning step in the third embodiment. For example, chlorine gas can be used as an etching gas when titanium is used as the material of the intermediate layer 50a.

  Titanium is more sensitive to chlorine than iridium. Therefore, when iridium is used for the first upper electrode 42, the intermediate layer 50a made of titanium is selected by setting the etching conditions to increase the chemical reactivity, such as increasing the pressure or decreasing the bias power. Can be removed.

  The first upper electrode 42 is formed in the first region 40A by the second patterning process. On the other hand, the first upper electrode 42, the intermediate layer 50, and the second upper electrode 44 are formed in the second region 40B. Therefore, the upper electrode 40 is formed such that the first region 40A is thinner than the second region 40B on the upper surface 32 of the piezoelectric layer 30.

  The intermediate layer 50 and the upper electrode 40 according to the present embodiment can be selected from materials that have a high selectivity in etching. For example, when etching the second upper electrode 44a, a material can be selected such that the etching rate of the second upper electrode 44a is larger than the etching rate of the intermediate layer 50a. In this case, the intermediate layer 50a can function as an etching stopper layer.

  In the etching of the intermediate layer 50a, a material or etching conditions can be selected such that the etching rate of the intermediate layer 50a is larger than the etching rate of the first upper electrode 42. In this case, the first upper electrode 42 can function as an etching stopper layer.

  As described above, in the piezoelectric element 130, the intermediate layer 50 in the first region 40A is removed by the second patterning step. Therefore, the piezoelectric element 130 according to the fourth embodiment can restrain the mechanical operation (deformation, etc.) of the piezoelectric body 30 in the first region 40A to be less restricted than the piezoelectric element 120 according to the third embodiment. it can.

5). 5. Fifth Embodiment 5.1 Piezoelectric Element Next, a piezoelectric element 140 according to a fifth embodiment will be described with reference to the drawings. FIG. 5 is a cross-sectional view schematically showing a piezoelectric element 140 according to the fifth embodiment, and corresponds to FIG. Hereinafter, in the piezoelectric element 140 according to the fifth embodiment, members having the same functions as those of the constituent members of the piezoelectric element 120 according to the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piezoelectric element 140 according to the fifth embodiment is different from the piezoelectric element 120 according to the third embodiment in that the intermediate layer 50 is provided on the side surface 34 of the piezoelectric layer 30. In other respects, the piezoelectric element 140 according to the fifth embodiment is the same as the piezoelectric element 120 according to the third embodiment.

  The intermediate layer 50 is formed on the side surface 34 of the piezoelectric layer 30 and may be positioned below the second upper electrode 44 on the side surface 34 of the piezoelectric layer 30. In the example of FIG. 5, the intermediate layer 50 is formed on the upper surface of the first upper electrode 42 in the first region 40A. In the example of FIG. 5, the intermediate layer 50 is formed between the first upper electrode 42 and the second upper electrode 44 in the second region 40B. In the example of FIG. 5, the intermediate layer 50 is formed below the second upper electrode 44 on the side surface 34 of the piezoelectric layer 30.

  One of the functions of the intermediate layer 50 in this embodiment is to suppress contact between the piezoelectric material of the piezoelectric layer 30 and moisture from the outside. That is, the intermediate layer 50 can have a barrier property that hardly allows moisture to pass therethrough. Therefore, deterioration of the piezoelectric material of the piezoelectric layer 30 covered with the intermediate layer 50 due to moisture or the like can be suppressed.

  Further, as one of the functions of the intermediate layer 50, it can have a function as an adhesion layer of the second upper electrode 44. Further, as one of the functions of the intermediate layer 50, a reaction caused by direct contact between the second upper electrode 44 and the piezoelectric layer 30 can be suppressed.

  The material of the intermediate layer 50 is not particularly limited as long as it has conductivity, but has a barrier property and high adhesion to the piezoelectric layer 30, the substrate 10, the first upper electrode 42, and the second upper electrode 44. Is preferable. The material of the intermediate layer 50 may have a function as a diffusion barrier for constituent elements of the second upper electrode 44 and the piezoelectric layer 30. Examples of the material of the intermediate layer 50 include various metals such as titanium, nickel, iridium, and platinum, their conductive oxides (for example, iridium oxide), SRO, LNO, titanium nitride, titanium aluminum nitride, and the like. Can do. Further, the intermediate layer 50 may be a single layer or a structure in which a plurality of layers are stacked.

  The second upper electrode 44 is not in contact with the piezoelectric layer 30 because the intermediate layer 50 is formed on the lower surface thereof. Therefore, the second upper electrode 44 is not easily oxidized by the piezoelectric layer 30. Therefore, as the material of the second upper electrode 44, in addition to the material of the upper electrode exemplified in the first embodiment, a material such as aluminum or copper that is relatively easily oxidized and diffused can be used. Further, if a material (for example, titanium) having good adhesion to the piezoelectric layer 30, the substrate 10, and the first upper electrode 42 is selected for the intermediate layer 50, the material of the second upper electrode 44 is Only the adhesiveness needs to be considered, and the material can be easily selected.

  As described above, the second upper electrode 44 in the fifth embodiment uses various materials compared to the upper electrode 40 (second upper electrode 44) in the first to fourth embodiments described above. it can.

5.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing the piezoelectric element, a method for manufacturing the piezoelectric element 140 of the above-described fifth embodiment will be exemplified and described with reference to the drawings. FIG. 20 is a cross-sectional view schematically showing the manufacturing process of the piezoelectric element 140. Hereinafter, in the method for manufacturing the piezoelectric element 140 according to the fifth embodiment, members having the same functions as those of the constituent members in the method for manufacturing the piezoelectric element 110 according to the second embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted. Description is omitted.

  The manufacturing method of the piezoelectric element 140 according to the fifth embodiment is that the intermediate layer 50a is formed after the first patterning process and before the second upper electrode 44a is formed, according to the piezoelectric element 110 according to the second embodiment. The manufacturing method is different. In other respects, the method for manufacturing the piezoelectric element 140 according to the fifth embodiment is the same as the method for manufacturing the piezoelectric element 110 according to the second embodiment.

  In the method for manufacturing the piezoelectric element 140 according to the fifth embodiment, the steps after the first patterning step can be performed as follows. First, as shown in FIG. 20, an intermediate layer 50 a is formed so as to cover the upper surface of the substrate 10, the side surface 34 of the piezoelectric layer 30, and the upper surface of the first upper electrode 42. As a method for forming the intermediate layer 50a, the same method as that for the intermediate layer 50a in the third embodiment described above can be used.

  Next, as shown in FIG. 20, the second upper electrode 44a is formed so as to cover the intermediate layer 50a. As a method of forming the second upper electrode 44a, the same method as the second upper electrode 44a in the third embodiment described above can be used.

  Except for the above steps, the piezoelectric element 140 according to the fifth embodiment can be obtained in the same manner as the method for manufacturing the piezoelectric element 120 according to the third embodiment. According to the method for manufacturing the piezoelectric element 140 of the present embodiment, the mechanical operation (deformation, etc.) of the piezoelectric element 140 can be restrained to a smaller extent, and the highly reliable piezoelectric element 140 can be easily manufactured. .

6). Sixth Embodiment 6.1 Piezoelectric Element Next, a piezoelectric element 150 according to a sixth embodiment will be described with reference to the drawings. FIG. 6 is a cross-sectional view schematically showing a piezoelectric element 150 according to the sixth embodiment, and corresponds to FIG. Hereinafter, in the piezoelectric element 150 according to the sixth embodiment, members having the same functions as those of the constituent members of the piezoelectric element 140 according to the fifth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piezoelectric element 150 according to the sixth embodiment is different from the piezoelectric element 140 according to the fifth embodiment in that the intermediate layer 50 is not provided in the first region 40A. In other respects, the piezoelectric element 150 according to the sixth embodiment is the same as the piezoelectric element 140 according to the fifth embodiment.

  The intermediate layer 50 may be formed on the side surface 34 of the piezoelectric layer 30, and may be formed on the lower surface of the second upper electrode 44 on the side surface 34 of the piezoelectric layer 30. In the example of FIG. 6, the intermediate layer 50 is formed between the first upper electrode 42 and the second upper electrode 44 in the second region 40B. In the example of FIG. 6, the intermediate layer 50 is formed on the lower surface of the second upper electrode 44 on the side surface 34 of the piezoelectric layer 30.

  In the piezoelectric element 150 according to the sixth embodiment, the intermediate layer 50 is not formed in the first region 40A. Therefore, the piezoelectric element 150 according to the sixth embodiment can restrain the mechanical operation (deformation, etc.) of the piezoelectric body 30 in the first region 40A to be less restricted than the piezoelectric element 140 according to the fifth embodiment. it can.

6.2 Method for Manufacturing Piezoelectric Element Next, as a method for manufacturing a piezoelectric element, a method for manufacturing the piezoelectric element 150 of the above-described sixth embodiment will be exemplified and described. Hereinafter, in the method for manufacturing the piezoelectric element 150 according to the sixth embodiment, members having the same functions as those of the constituent members in the method for manufacturing the piezoelectric element 140 according to the fifth embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted. Description is omitted.

  The manufacturing method of the piezoelectric element 150 according to the sixth embodiment is different from the manufacturing method of the piezoelectric element 140 according to the fifth embodiment in that the patterning of the intermediate layer 50a is added in the second patterning step. In other respects, the method for manufacturing the piezoelectric element 150 according to the sixth embodiment is the same as the method for manufacturing the piezoelectric element 140 according to the fifth embodiment.

  In the manufacturing method of the piezoelectric element 150 according to the sixth embodiment, the processes up to the second patterning step can be performed in the same manner as the manufacturing method of the piezoelectric element 140 according to the fifth embodiment. Further, the second and subsequent patterning steps can be performed in the same manner as the method for manufacturing the piezoelectric element 130 according to the fourth embodiment.

  As described above, the piezoelectric element 150 according to the sixth embodiment can be obtained. In the piezoelectric element 150, the intermediate layer 50 in the first region 40A is removed by the second patterning step. Therefore, the piezoelectric element 150 according to the sixth embodiment can restrain the mechanical operation (deformation and the like) of the piezoelectric body 30 in the first region 40A to be less restricted than the piezoelectric element 140 according to the fifth embodiment. it can.

7). Seventh Embodiment Next, a liquid jet head in which the piezoelectric element according to the present invention functions as a piezoelectric actuator will be described with reference to the drawings. FIG. 21 is a cross-sectional view schematically showing the main part of the liquid jet head 400. FIG. 22 is an exploded perspective view of the liquid ejecting head 400, which is shown upside down from a state in which it is normally used.

  The liquid ejecting head 400 can include the above-described piezoelectric element (piezoelectric actuator). In the following example, a liquid ejecting head 400 having the piezoelectric element 100 as a piezoelectric actuator will be described. As described above, when the piezoelectric element 100 functions as a piezoelectric actuator, the substrate 10 is a diaphragm that has flexibility and is deformed by the operation of the piezoelectric layer 30.

  Further, the liquid ejecting head 400 in FIG. 21 shows a structure in which a plurality of piezoelectric elements 100 according to the first embodiment are formed, but a plurality of piezoelectric elements in other embodiments described above can be formed in the same manner. Hereinafter, in the liquid ejecting head 400, members having the same functions as those of the piezoelectric element 100 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 21, the liquid ejecting head 400 includes a laminated structure 200 including a lower electrode 20, a piezoelectric layer 30, and an upper electrode 40, and a plurality of laminated structures 200 are formed. is there. In the example of FIG. 21, three stacked structures 200 are provided, but the number is not particularly limited.

  The upper electrode 40 is a common electrode in the plurality of stacked structures 200. The lower electrode 20 is an individual electrode in the plurality of stacked structures 200 and is electrically separated.

  As shown in FIGS. 21 and 22, the liquid ejecting head 400 includes a nozzle plate 410 having nozzle holes 412, a pressure chamber substrate 420 for forming the pressure chamber 422, and the piezoelectric element 100. Furthermore, the liquid ejecting head 600 can include a housing 430 as illustrated in FIG. In FIG. 22, the laminated structure 200 of the piezoelectric element 100 is illustrated in a simplified manner.

  The nozzle plate 410 has nozzle holes 412 as shown in FIGS. 21 and 22. Ink can be ejected from the nozzle holes 412. In the nozzle plate 410, for example, a number of nozzle holes 412 are provided in a row. Examples of the material of the nozzle plate 420 include silicon and stainless steel (SUS).

  The pressure chamber substrate 420 is provided on the nozzle plate 410 (lower in the example of FIG. 22). Examples of the material of the pressure chamber substrate 420 include silicon. When the pressure chamber substrate 420 divides the space between the nozzle plate 410 and the substrate 10, as shown in FIG. 22, a reservoir (liquid storage portion) 424, a supply port 426 communicating with the reservoir 424, and a supply port A pressure chamber 422 communicating with 426 is provided. That is, the reservoir 424, the supply port 426, and the pressure chamber 422 are partitioned by the nozzle plate 410, the pressure chamber substrate 420, and the substrate 10. The reservoir 424 can temporarily store ink supplied from the outside (for example, an ink cartridge) through a through hole 428 provided in the substrate 10. The ink in the reservoir 424 can be supplied to the pressure chamber 422 via the supply port 426. The volume of the pressure chamber 422 changes due to the deformation of the substrate 10. The pressure chamber 422 communicates with the nozzle hole 412, and ink or the like is ejected from the nozzle hole 412 when the volume of the pressure chamber 422 changes.

  The piezoelectric element 100 is provided on the pressure chamber substrate 420 (lower in the example of FIG. 22). The laminated structure 200 of the piezoelectric element 100 is electrically connected to a piezoelectric element driving circuit (not shown) and can operate (vibrate or deform) based on a signal from the piezoelectric element driving circuit. The substrate 10 can be deformed by the operation of the laminated structure 200 (piezoelectric layer 30), and the internal pressure of the pressure chamber 422 can be appropriately changed.

  As shown in FIG. 22, the housing 430 can accommodate the nozzle plate 410, the pressure chamber substrate 420, and the piezoelectric element 100. Examples of the material of the housing 430 include a resin and a metal.

  The liquid ejecting head 400 includes the highly reliable piezoelectric element 100 described above. Therefore, the liquid ejecting head 400 is highly reliable.

  Here, the case where the liquid ejecting head 400 is an ink jet recording head has been described. However, the liquid jet head of the present invention includes, for example, a color material jet head used for manufacturing a color filter such as a liquid crystal display, an electrode material jet head used for forming an electrode such as an organic EL display, FED (surface emitting display), It can also be used as a bioorganic matter ejecting head used for biochip manufacture.

8). Eighth Embodiment Next, a liquid ejecting apparatus according to the present embodiment will be described with reference to the drawings. FIG. 23 is a perspective view schematically showing the liquid ejecting apparatus 500 according to the present embodiment. The liquid ejecting apparatus 500 includes the liquid ejecting head according to the invention. Hereinafter, a case where the liquid ejecting apparatus 500 is an ink jet printer having the above-described liquid ejecting head 400 will be described.

  As shown in FIG. 23, the liquid ejecting apparatus 500 includes a head unit 530, a driving unit 510, and a control unit 560. Further, the liquid ejecting apparatus 500 includes an apparatus main body 520, a paper feed unit 550, a tray 521 in which the recording paper P is placed, a discharge port 522 for discharging the recording paper P, and an operation disposed on the upper surface of the apparatus main body 520. A panel 570.

  The head unit 530 includes an ink jet recording head (hereinafter, also simply referred to as “head”) including the liquid ejecting head 400 described above. The head unit 530 further includes an ink cartridge 531 that supplies ink to the head, and a transport unit (carriage) 532 on which the head and the ink cartridge 531 are mounted.

  The drive unit 510 can reciprocate the head unit 530. The drive unit 510 includes a carriage motor 541 serving as a drive source for the head unit 530, and a reciprocating mechanism 542 that reciprocates the head unit 530 in response to the rotation of the carriage motor 541.

  The reciprocating mechanism 542 includes a carriage guide shaft 544 whose both ends are supported by a frame (not shown), and a timing belt 543 extending in parallel with the carriage guide shaft 544. The carriage guide shaft 544 supports the carriage 532 while allowing the carriage 532 to freely reciprocate. Further, the carriage 532 is fixed to a part of the timing belt 543. When the timing belt 543 is caused to travel by the operation of the carriage motor 541, the head unit 530 is reciprocated by being guided by the carriage guide shaft 544. During this reciprocation, ink is appropriately discharged from the head, and printing on the recording paper P is performed.

  The control unit 560 can control the head unit 530, the driving unit 510, and the paper feeding unit 550.

  The paper feed unit 550 can feed the recording paper P from the tray 521 to the head unit 530 side. The sheet feeding unit 550 includes a sheet feeding motor 551 serving as a driving source thereof, and a sheet feeding roller 552 that is rotated by the operation of the sheet feeding motor 551. The paper feed roller 552 includes a driven roller 552a and a drive roller 552b that are vertically opposed to each other across the feeding path of the recording paper P. The drive roller 552b is connected to the paper feed motor 551. When the paper supply unit 550 is driven by the control unit 560, the recording paper P is sent so as to pass below the head unit 530.

  The head unit 530, the drive unit 510, the control unit 560, and the paper feeding unit 550 are provided inside the apparatus main body 520.

  The liquid ejecting apparatus 500 has a highly reliable liquid ejecting head 400. Therefore, the reliability of the liquid ejecting apparatus 500 is high.

  In the above-described example, the case where the liquid ejecting apparatus 500 is an ink jet printer has been described. However, the liquid ejecting apparatus of the present invention can also be used as an industrial liquid ejecting apparatus. As the liquid (liquid material) discharged in this case, various functional materials adjusted to an appropriate viscosity with a solvent or a dispersion medium can be used.

  In addition, embodiment mentioned above and a modification are examples, Comprising: It is not necessarily limited to these. For example, a plurality of embodiments and modifications can be combined as appropriate.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

10 substrate, 12 silicon substrate, 14 zirconia layer, 20 lower electrode, 30, 30a piezoelectric layer, 40, 40a upper electrode, 40A first region, 40B second region, 42, 42a first upper electrode, 44, 44a first 2 Upper electrode, 50, 50a Intermediate layer, 100, 110, 120, 130, 140, 150 Piezoelectric element, 200 Laminated structure, 400 Liquid jet head, 410 Nozzle plate, 412 Nozzle hole, 420 Pressure chamber substrate, 422 Pressure chamber 424 reservoir, 426 supply port, 428 through hole, 430 housing, 500 liquid ejection device, 510 drive unit, 520 device main body, 521 tray, 522 discharge port, 530 head unit, 531 ink cartridge, 532 carriage, 541 carriage motor , 542 Reciprocating mechanism, 543 Timing belt, 544 a carriage guide shaft, 550 paper feeding unit, 551 paper feed motor, 552 feed roller, 552a driven roller, 552b drive rollers, 560 control unit, 570 operation panel

Claims (8)

A substrate,
A lower electrode formed above the substrate;
A piezoelectric layer formed to cover a side surface and an upper surface of the lower electrode;
An upper electrode formed to cover a side surface and an upper surface of the piezoelectric layer;
Including
The upper electrode has a first region and a second region on the upper surface of the piezoelectric layer,
The first region includes at least a part of a region overlapping the lower electrode in plan view,
The second region is a region other than the first region,
The first region is a piezoelectric element having a thickness smaller than that of the second region. In claim 1,
The upper electrode has a first upper electrode and a second upper electrode,
The first upper electrode is formed on an upper surface of the piezoelectric layer,
The second upper electrode is a piezoelectric element formed on a side surface of the piezoelectric layer and the second region, and formed on an upper surface of the first upper electrode in the second region. In claim 2,
Furthermore, it has an intermediate layer,
The intermediate layer is formed in the first region and the second region, and is located between the first upper electrode and the second upper electrode. In claim 2,
Furthermore, it has an intermediate layer,
The intermediate layer is formed in the second region, and is located between the first upper electrode and the second upper electrode. In claim 3 or claim 4,
Furthermore, the intermediate layer is formed on a side surface of the piezoelectric layer, and is located below the second upper electrode on the side surface of the piezoelectric layer. Including the piezoelectric element according to any one of claims 1 to 5,
The substrate is a piezoelectric actuator that is deformed by the operation of the piezoelectric layer. A piezoelectric actuator according to claim 6;
A pressure chamber in communication with the nozzle hole, the volume of which is changed by the operation of the piezoelectric actuator;
Including a liquid jet head.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 7.

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