JP2014179390A - Actuator device, liquid injection head, and liquid injection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator device, containing no lead, having no problem such as film peeling, and free from degradation of piezoelectric characteristics, and to provide a liquid injection head and a liquid injection apparatus.SOLUTION: The actuator device includes: an adhesion layer (56) provided on a substrate; a first electrode (60) provided on the adhesion layer; a piezoelectric layer (70) provided on the first electrode (60); and a second electrode (80) provided on the piezoelectric layer. The adhesion layer is composed of an aluminum oxide, and the piezoelectric layer is composed of a complex oxide of a perovskite structure containing bismuth, iron, barium, and titanium.

Description

  The present invention relates to an actuator device, a liquid ejecting head, and a liquid ejecting apparatus having a piezoelectric element provided with a piezoelectric layer and electrodes on both sides thereof.

  As a piezoelectric element used in an ink jet recording head as a typical example of a liquid ejecting head, a piezoelectric material exhibiting an electromechanical conversion function, for example, a piezoelectric layer made of piezoelectric ceramics is sandwiched between two electrodes. There is something. Such a piezoelectric element is mounted on a liquid ejecting head as an actuator device in a flexural vibration mode.

A piezoelectric material used as a piezoelectric layer constituting such a piezoelectric element is required to have high piezoelectric characteristics, and a typical example of a piezoelectric material is lead zirconate titanate (PZT). From the viewpoint, there is a demand for a piezoelectric material with reduced lead or lead content. As a piezoelectric material not containing lead, for example, there is a BiFeO ₃ -based piezoelectric material containing Bi and Fe (see, for example, Patent Document 1).

BiFeO ₃ -based piezoelectric material containing Bi and Fe is promising as an alternative material for PZT as the above-described piezoelectric material not containing lead. However, when a piezoelectric element is formed using such a piezoelectric material, There is a problem in that film detachment occurs due to diffusion of bismuth to the electrode side.

  Specifically, like a piezoelectric element using PZT, a first electrode such as platinum is formed on a dielectric layer such as zirconium oxide using a titanium oxide film as an adhesion layer, and then a bismuth-based piezoelectric material. When the piezoelectric layer made of is formed, bismuth diffuses into the first electrode, and further, bismuth segregates at the boundary with the adhesion layer below, which causes film peeling. Further, when titanium is used as the adhesion layer, there is a problem that bismuth diffuses into the first electrode and at the same time titanium diffuses into the first electrode and further into the piezoelectric layer, thereby deteriorating the characteristics of the piezoelectric layer.

  Therefore, a technique for forming an adhesion layer made of zirconium on an insulator film made of zirconium oxide has been proposed (see Patent Document 2).

JP 2007-287745 A JP 2012-204549 A

  However, even with the technique of Patent Document 2, there is a problem that when high-temperature firing is performed in order to improve the piezoelectric characteristics of the piezoelectric layer, film peeling tends to occur and sufficient durability cannot be obtained.

  In any case, when a piezoelectric element is formed using a bismuth-based piezoelectric material that does not contain lead, it is difficult to form a piezoelectric element that maintains adhesion with the base and has excellent piezoelectric characteristics. .

  Such a problem is not limited to the ink jet recording head, and is a problem common to liquid ejecting heads. Further, this is a problem common not only to piezoelectric elements used in liquid jet heads but also to piezoelectric elements used in other devices such as ultrasonic devices.

  In view of such circumstances, it is an object of the present invention to provide an actuator device, a liquid ejecting head, and a liquid ejecting device that do not contain lead, have no problems such as film peeling, and have no deterioration in piezoelectric characteristics.

An aspect of the present invention that solves the above problems includes an adhesion layer provided on a substrate, a first electrode provided on the adhesion layer, a piezoelectric layer provided on the first electrode, and the piezoelectric body. A second electrode provided on the layer, wherein the adhesion layer is made of aluminum oxide, and the piezoelectric layer is made of a complex oxide having a perovskite structure containing bismuth, iron, barium, and titanium. There is an actuator device to do.
In such an embodiment, by providing aluminum oxide as the adhesion layer, even if the piezoelectric layer is formed at a firing temperature of 750 ° C. or higher, a high-performance actuator device with excellent durability and no film peeling can be realized.

  Here, the adhesion layer is preferably formed by a CVD method or a chemical solution method. According to this, the adhesion layer excellent in adhesion can be formed relatively easily.

  Moreover, it is preferable that the said adhesion layer is formed by the chemical solution method on the conditions whose calcination temperature is 750 degreeC or more. According to this, peeling of the film can be prevented more reliably, and a high-performance actuator device with excellent durability can be realized.

  Moreover, it is preferable that the adhesion layer is formed under a condition where the firing temperature is 850 ° C. or higher. According to this, peeling of the film can be prevented more reliably, and a high-performance actuator device with excellent durability can be realized.

  Moreover, it is preferable that the thickness of the said adhesion layer is 10-50 nm. According to this, it can be set as the contact | adherence layer which exhibits the outstanding adhesiveness.

According to another aspect of the invention, there is provided a liquid ejecting head including the actuator device according to the above aspect.
In such an embodiment, it is possible to realize a high-performance liquid ejecting head having no film peeling and excellent durability.

Another aspect of the invention is a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
According to this aspect, it is possible to realize a liquid ejecting apparatus including a high-performance liquid ejecting head that has no film peeling and excellent durability.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.

(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head which is an example of a liquid jet head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. 1 and a cross-sectional view taken along line AA ′ in FIG. .
As shown in FIGS. 1 to 2, the flow path forming substrate 10 of the present embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.

  A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14 and a communication path 15. The communication part 13 communicates with a manifold part 31 of a protective substrate, which will be described later, and constitutes a part of a manifold that becomes a common ink chamber for each pressure generating chamber 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13. In this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. In the present embodiment, the flow path forming substrate 10 is provided with a liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the elastic film 50 is made of, for example, zirconium oxide (ZrO ₂ ). Insulator layer 55 is laminated.

  Further, an adhesion layer 56 made of aluminum oxide is provided on the insulator layer 55. The adhesion layer 56 can secure the adhesion strength with the first electrode 60 even if a piezoelectric layer 70 described later is baked at a high temperature of 750 to 850 ° C. The adhesion layer 56 made of aluminum oxide can be formed by a CVD method or a chemical solution method, and may be provided with a thickness of about 10 nm to 100 nm, preferably about 10 to 50 nm.

  On the adhesion layer 56, the first electrode 60 is provided above the first electrode 60, and is provided on the orientation control layer 65 having a thickness of, for example, 20 to 80 nm, and the orientation control layer 65. A piezoelectric layer 70 that is a thin film having a thickness of 3 μm or less, preferably 0.3 to 1.5 μm, and a second electrode 80 provided above the piezoelectric layer 70 are laminated to form a piezoelectric element. 300. In addition, the upper direction said here includes not only immediately above but the state where the other member intervened. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80.

  In the piezoelectric element 300, generally, one of the electrodes is a common electrode, and the other electrode is an independent electrode. In the present embodiment, the first electrode 60 is provided as an individual electrode of each piezoelectric active part that is a substantial driving part of the piezoelectric element 300, and the second electrode 80 is provided as a common electrode common to a plurality of piezoelectric active parts. I did it. Here, a portion where piezoelectric distortion is caused by application of voltage to both electrodes is referred to as a piezoelectric active portion, which is continuous from the piezoelectric active portion but is not sandwiched between the first electrode 60 and the second electrode 80, and is voltage driven. The part that is not used is called a piezoelectric non-active part. In addition, the piezoelectric element 300 and a vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric element, but may be referred to as an actuator device.

  In the above-described example, the elastic film 50, the insulator layer 55, and the first electrode 60 act as a diaphragm that is deformed together with the piezoelectric element 300. However, the present invention is not limited to this, and for example, the elastic film 50 In addition, without providing the insulator layer 55, only the first electrode 60 may function as a diaphragm. However, when the first electrode 60 is provided directly on the flow path forming substrate 10, it is preferable to protect the first electrode 60 with an insulating protective film or the like so that the first electrode 60 and the ink are not electrically connected.

The orientation control layer 65 has a perovskite structure, is a complex oxide in which the A site contains Bi and the B site contains Fe and Ti, and is self-oriented in the (100) plane. Specifically, the A site of the ABO ₃ type structure has 12 coordinated oxygen, and the B site has 6 coordinated oxygen to form an octahedron. The complex oxide constituting the orientation control layer 65 is preferably basically composed of Bi at the A site and Fe and Ti at the B site. A preferable composition ratio is preferably in the range of 40 ≦ x ≦ 60 when the element ratio is represented by Bi: Fe: Ti = 100: x: (100−x). The composite oxide having such a composition ratio is self-oriented in the (100) plane without being affected by the base, and the piezoelectric material having a perovskite structure formed thereon is oriented in the (100) plane. It functions as an orientation control layer. That is, although details will be described later, since the orientation control layer 65 is formed after patterning the first electrode 60, it is formed on the first electrode 60 and the insulator layer 55. The piezoelectric layer 70 that self-orients in the (100) plane on any base, and can be surely preferentially oriented in the (100) plane, in particular, the first electrode 60 and the insulator layer 55. Even in the vicinity of the boundary, the nonuniformity of the crystal state of the piezoelectric layer 70 is reduced.

  Here, self-orientation in the (100) plane means that it is oriented in the (100) plane without being affected by the base, and almost all the crystals are oriented in the (100) plane. In which the crystal (for example, 80% or more) is oriented in the (100) plane.

In addition, as long as such a function is not hindered, a composite oxide in which a part of the elements at the A site and the B site is substituted with other elements may be included in the alignment control layer of the present invention. For example, in addition to Bi, elements such as Ba, Sr, and La may further exist at the A site, and elements such as Zr and Nb may also exist along with Fe and Ti at the B site. In addition, as long as it has the above-described function, those that deviate from the stoichiometric composition (ABO ₃ ) due to deficiency or excess of the elements (Bi, Fe, Ti, O) are also included in the orientation control layer of the present invention. For example, it has been confirmed that a composite oxide containing Bi in excess of the stoichiometric ratio is self-oriented in the (100) plane and functions as an orientation control layer, as will be described later.

  The orientation control layer 65 has a perovskite structure similar to that of the piezoelectric material forming the piezoelectric layer 70 described later, and has a small but piezoelectric property. The orientation control layer 65 and the piezoelectric layer 70 are made of It can also be referred to as a piezoelectric layer.

In this embodiment, the piezoelectric material constituting the piezoelectric layer 70 is a complex oxide having a perovskite structure including bismuth (Bi), iron (Fe), barium (Ba), and titanium (Ti). In the A site of the perovskite structure, that is, the ABO ₃ type structure, oxygen is 12-coordinated, and in the B site, oxygen is 6-coordinated to form an octahedron. Bi and Ba are located at the A site, and Fe and Ti are located at the B site.

  Such a composite oxide containing Bi, Fe, Ba and Ti and having a perovskite structure is a composite oxide having a perovskite structure of a mixed crystal of bismuth ferrate and barium titanate, or bismuth ferrate and barium titanate. Is also expressed as a solid solution in which the solid solution is uniformly dissolved. In the X-ray diffraction pattern, bismuth ferrate and barium titanate are not detected alone.

Here, bismuth ferrate and barium titanate are known piezoelectric materials each having a perovskite structure, and those having various compositions are known. For example, as bismuth ferrate or barium titanate, in addition to BiFeO ₃ or BaTiO ₃ , some elements (Bi, Fe, Ba, Ti, O) are partially lost or excessive, or some of the elements are other elements However, in the present invention, when expressed as bismuth ferrate or barium titanate, a component deviating from the stoichiometric composition due to deficiency or excess or a part of the element is replaced by another element. Those substituted are also included in the ranges of bismuth ferrate and barium titanate. The ratio of bismuth ferrate to barium titanate can also be changed variously.

The composition of the piezoelectric layer 70 made of a complex oxide having such a perovskite structure is represented, for example, as a mixed crystal represented by the following general formula (1). Moreover, this formula (1) can also be represented by the following general formula (1 ′). Here, the description of the general formula (1) and the general formula (1 ′) is a composition notation based on stoichiometry, and as described above, as long as a perovskite structure can be taken, it is inevitable due to lattice mismatch, oxygen deficiency, etc. Of course, a partial substitution of elements is allowed as well as a slight compositional deviation. For example, if the stoichiometric ratio is 1, the range of 0.85 to 1.20 is allowed. In addition, even when the general formulas are different as described below, those having the same ratio of the A-site element to the B-site element may be regarded as the same composite oxide.
(1-x) [BiFeO ₃ ] -x [BaTiO ₃ ] (1)
(0 <x <0.40)
(Bi _1-x Ba _x ) (Fe _1-x Ti _x ) O ₃ (1 ′)
(0 <x <0.40)

  Further, the composite oxide constituting the piezoelectric layer 70 of the present embodiment may further include an element other than Bi, Fe, Ba, and Ti. Examples of other elements include Mn, Co, and Cr. Also in the case of a complex oxide containing these other elements, it is preferable to have a perovskite structure.

  When the piezoelectric layer 70 contains Mn, Co, and Cr, Mn, Co, and Cr are complex oxides having a structure located at the B site of the perovskite structure. For example, when Mn is included, the composite oxide constituting the piezoelectric layer 70 has a structure in which part of Fe in a solid solution in which bismuth ferrate and barium titanate are uniformly dissolved, is substituted with Mn, or ferric acid It is expressed as a composite oxide having a perovskite structure of mixed crystals of bismuth manganate and barium titanate, and the basic characteristics are the same as those of a composite oxide having a perovskite structure of mixed crystals of bismuth ferrate and barium titanate. However, it has been found that the leakage characteristics are improved. Further, when Co or Cr is included, the leakage characteristics are improved in the same manner as Mn. In the X-ray diffraction pattern, bismuth ferrate, barium titanate, bismuth iron manganate, bismuth iron cobaltate, and bismuth iron chromate are not detected alone. Further, although Mn, Co and Cr have been described as examples, it has been found that leakage characteristics are similarly improved when two other transition metal elements are included at the same time. In addition, other known additives may be included to improve the properties.

The piezoelectric layer 70 made of a composite oxide having a perovskite structure including Mn, Co, and Cr in addition to Bi, Fe, Ba, and Ti is, for example, a mixed crystal represented by the following general formula (2). is there. Moreover, this formula (2) can also be represented by the following general formula (2 ′). In General Formula (2) and General Formula (2 ′), M is Mn, Co, or Cr. Here, the description of the general formula (2) and the general formula (2 ′) is a composition notation based on the stoichiometry, and as described above, as long as the perovskite structure can be taken, it is unavoidable due to lattice mismatch, oxygen deficiency, etc. Such a composition deviation is allowed. For example, if the stoichiometry is 1, one in the range of 0.85 to 1.20 is allowed. In addition, even when the general formulas are different as described below, those having the same ratio of the A-site element to the B-site element may be regarded as the same composite oxide.
(1-x) [Bi (Fe _{1- y My} ) O ₃ ] -x [BaTiO ₃ ] (2)
(0 <x <0.40, 0.01 <y <0.10)
_{(Bi 1-x Ba x)} ((Fe 1-y M y) 1-x Ti x) O 3 (2 ')
(0 <x <0.40, 0.01 <y <0.10)

  The second electrode 80 may be any of various metals such as Ir, Pt, tungsten (W), tantalum (Ta), and molybdenum (Mo), and alloys thereof and metal oxides such as iridium oxide. It is done.

  The second electrode 80 of each piezoelectric element 300 is made of gold (Au) or the like drawn from the vicinity of the end on the ink supply path 14 side and extended on the insulator layer 55 of the flow path forming substrate 10. Lead electrodes 90 are connected to each other. A voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90.

  On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, that is, on the first electrode 60, the elastic film 50, and the lead electrode 90, a protection having a manifold portion 31 constituting at least a part of the manifold 100. The substrate 30 is bonded via an adhesive 35. In this embodiment, the manifold portion 31 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12. As described above, the communication portion 13 of the flow path forming substrate 10. The manifold 100 is configured as a common ink chamber for the pressure generation chambers 12.

  A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used.

  The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  A drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the manifold portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of the present embodiment, ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the manifold 100 to the nozzle opening 21 is filled with ink, and then the drive circuit 120. In accordance with the recording signal from the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, the elastic film 50, the insulator layer 55, the first electrode 60, and the piezoelectric layer. By bending and deforming 70, the pressure in each pressure generating chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

  Next, an example of a method for manufacturing the ink jet recording head of this embodiment will be described with reference to FIGS. 3 to 6 are cross-sectional views in the longitudinal direction (second direction) of the pressure generating chamber.

First, as shown in FIG. 3A, a silicon dioxide film made of silicon dioxide (SiO ₂ ) or the like that constitutes the elastic film 50 is formed on the surface of a wafer for flow path formation substrate that is a silicon wafer. Next, as shown in FIG. 3B, an insulator layer 55 made of zirconium oxide or the like is formed on the elastic film 50 (silicon dioxide film). Next, as shown in FIG. 3C, an adhesion layer 56 made of aluminum oxide is formed on the insulator layer 55. The adhesion layer 56 may be formed by a CVD method or a chemical solution method. In this embodiment, the adhesion layer 56 is formed by a chemical solution method. Specifically, a coating solution containing an aluminum oxide precursor is spin-coated, and preferably fired at a temperature higher than the firing temperature of the piezoelectric layer 70, for example, 850 to 950 ° C. Thereby, adhesiveness with the 1st electrode 60 provided on this is ensured, and adhesiveness is ensured also when the piezoelectric material layer 70 is baked at a high temperature of 750-850 degreeC. In addition, when forming a contact | adherence layer by a chemical solution method, as above-mentioned, baking at 850 degreeC or more is preferable, and when baking at 800 degreeC, film | membrane peeling was confirmed.

  Next, as shown in FIG. 4A, a first electrode 60 made of platinum is formed on the entire surface of the adhesion layer 56 by sputtering or vapor deposition. Next, as shown in FIG. 4B, the first electrode 60 is patterned on the first electrode 60 using a resist (not shown) having a predetermined shape as a mask.

  Next, as shown in FIG. 4C, after removing the resist, a perovskite structure in which the A site contains Bi and the B site contains Fe and Ti is formed on the first electrode 60 (and the insulator layer 55). An alignment control layer precursor layer 66, which is a precursor to be a composite oxide, is formed and fired to obtain an alignment control layer 65 made of a composite oxide having a perovskite structure (FIG. 4D). . Thus, the orientation control layer 65 is made of, for example, a metal oxide by applying a precursor solution containing a metal complex to form the orientation control layer precursor layer 66, drying it, and firing it at a higher temperature. The alignment control layer 65 can be obtained by using a chemical solution method such as a MOD (Metal-Organic Decomposition) method or a sol-gel method. In addition, the alignment control layer 65 can also be manufactured by a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.

  Next, a piezoelectric layer 70 made of a complex oxide having a perovskite structure is formed on the orientation control layer 65. The piezoelectric layer 70 can be manufactured, for example, by applying and drying a solution containing a metal complex and degreasing. In addition, the piezoelectric layer 70 can also be manufactured by a laser ablation method, a sputtering method, a pulse laser deposition method (PLD method), a CVD method, an aerosol deposition method, or the like.

  For example, first, as shown in FIG. 5A, a sol or MOD solution (precursor solution) containing an organometallic complex containing a constituent metal of a piezoelectric material to be the piezoelectric layer 70 is formed on the orientation control layer 65. The piezoelectric precursor film 71 is formed by coating using a spin coating method or the like (coating process).

  The precursor solution to be applied is prepared by, for example, mixing organometallic complexes each containing a constituent metal of the piezoelectric material that becomes the piezoelectric layer 70 so that each constituent metal has a desired molar ratio, and mixing the mixture with an organic material such as alcohol. It is dissolved or dispersed using a solvent. As the organometallic complex containing the constituent metal of the piezoelectric material, for example, a metal alkoxide, an organic acid salt, a β-diketone complex, or the like can be used. Specific examples include the following. Examples of the organometallic complex containing lead (Pb) include lead acetate. Examples of the organometallic complex containing zirconium (Zr) include zirconium acetylacetonate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate and the like. Examples of the organometallic complex containing titanium (Ti) include titanium alkoxide and titanium isopropoxide.

Next, the piezoelectric precursor film 71 is heated to a predetermined temperature, for example, about 130 ° C. to 180 ° C. and dried for a predetermined time (drying step). Next, the dried piezoelectric precursor film 71 is degreased by heating to a predetermined temperature, for example, 300 ° C. to 400 ° C., and holding it for a certain time (degreasing step). In addition, degreasing said here is separating the organic component contained in the piezoelectric precursor film 71 as, for example, NO ₂ , CO ₂ , H ₂ O or the like.

  Next, as shown in FIG. 5B, the piezoelectric precursor film 71 is crystallized by heating to a predetermined temperature, for example, about 750 to 850 ° C. and holding for a certain period of time, thereby forming the piezoelectric film 72. (Baking process). Examples of the heating device used in the drying step, the degreasing step, and the firing step include an RTA (Rapid Thermal Annealing) device that heats by irradiation with an infrared lamp, a hot plate, and the like.

  In addition, by repeating the coating process, the drying process and the degreasing process described above, and the coating process, the drying process, the degreasing process, and the firing process a plurality of times according to a desired film thickness, etc., a piezoelectric body composed of a plurality of piezoelectric films A layer may be formed.

  Next, the above-described coating process, drying process, degreasing process, coating process, drying process, degreasing process, and firing process are repeated a plurality of times in accordance with a desired film thickness and the like, and the piezoelectric layer 70 composed of a plurality of piezoelectric films 72. As shown in FIG. 5C, a piezoelectric layer 70 having a predetermined thickness composed of a plurality of layers of piezoelectric films 72 is formed. For example, when the film thickness of the coating solution per one time is about 0.1 μm, for example, the entire film thickness of the piezoelectric layer 70 composed of the ten piezoelectric films 72 is about 1.1 μm. In the present embodiment, the piezoelectric film 72 is provided by being laminated, but only one layer may be provided.

  As described above, the orientation control layer 65 is formed by forming the piezoelectric layer 70 on the orientation control layer 65 made of a complex oxide having a perovskite structure in which the predetermined A site contains Bi and the B site contains Fe and Ti. Thus, the orientation of the piezoelectric layer 70 is controlled, and the piezoelectric layer 70 preferentially oriented in the (100) plane can be obtained.

  After the piezoelectric layer 70 is formed, as shown in FIG. 6A, a second electrode 80 made of a metal such as platinum is laminated on the piezoelectric layer 70, and the piezoelectric layer 70 and the second layer The electrode 80 is simultaneously patterned to form the piezoelectric element 300. The patterning of the piezoelectric layer 70 and the second electrode 80 can be performed collectively by dry etching via a resist (not shown) formed in a predetermined shape. Thereafter, post-annealing may be performed in a temperature range of 700 ° C. or lower as necessary. Thereby, a good interface between the piezoelectric layer 70 and the first electrode 60 or the second electrode 80 can be formed, and the crystallinity of the piezoelectric layer 70 can be improved.

  Next, as shown in FIG. 6B, a lead electrode 90 made of, for example, gold (Au) or the like is formed over the entire surface of the wafer 110 for flow path forming substrate, and then a mask pattern made of, for example, a resist or the like. Patterning is performed for each piezoelectric element 300 via (not shown).

  Next, as shown in FIG. 6C, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is placed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 with an adhesive 35 interposed therebetween. After the bonding, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, although not shown, a mask film is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, by performing anisotropic etching (wet etching) using an alkaline solution such as KOH on the flow path forming substrate wafer 110 through the mask film, the pressure generating chamber 12 corresponding to the piezoelectric element 300, the communication portion 13, An ink supply path 14 and a communication path 15 are formed.

  Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. Then, after removing the mask film on the surface opposite to the protective substrate wafer 130 of the flow path forming substrate wafer 110, the nozzle plate 20 having the nozzle openings 21 formed therein is bonded, and the protective substrate wafer 130 is bonded. The compliance substrate 40 is bonded, and the flow path forming substrate wafer 110 and the like are divided into a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, thereby forming the ink jet recording head I of this embodiment. .

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.

Example 1
A silicon oxide (SiO ₂ ) film having a thickness of 1200 nm was formed on the surface of a (110) single crystal silicon (Si) substrate by thermal oxidation. Next, a 400 nm-thickness zirconium film was formed on the SiO ₂ film by DC sputtering, and this was heat-treated (RTA) in an oxygen atmosphere to form a zirconia layer. An aluminum oxide precursor solution was spin-coated on this zirconia layer as an adhesion layer, and baked at 850 ° C., thereby forming an adhesion layer made of aluminum oxide having a thickness of 40 nm.

  Next, a platinum film (first electrode 60) having a thickness of 100 nm and oriented in the (111) plane was formed by DC sputtering.

  Next, each n-octane solution of bismuth 2-ethylhexanoate, iron 2-ethylhexanoate, and titanium 2-ethylhexanoate is mixed, and the molar ratio of Bi: Fe: Ti becomes 100: 40: 60. By mixing at a ratio, an alignment control layer precursor solution was prepared. The orientation control layer precursor solution is formed on the substrate with electrodes by a spin coater and then baked on a hot plate at 180 ° C. × 3 min and 350 ° C. × 3 min to form an amorphous film. Next, firing was performed at 700 ° C. for 5 minutes using a lamp annealing furnace to obtain an orientation control layer having a thickness of 80 nm.

Next, bismuth manganate (BiMnO ₃ ) was coated by a sol-gel method and RTA baked at 750 ° C. for 5 minutes to form a 20 nm thin film. The orientation control was performed using this layer as a seed layer.

  Next, a piezoelectric film was laminated on the first electrode 60 to form a piezoelectric layer 70. The method is as follows. First, each n-octane solution of bismuth 2-ethylhexanoate, iron 2-ethylhexanoate, manganese 2-ethylhexanoate, barium 2-ethylhexanoate and titanium 2-ethylhexanoate, each element in molar ratio A precursor solution was prepared by mixing Bi: Ba: Fe: Ti: Mn = 75: 25: 71.25: 25: 3.75 (BFO: BT = 75: 25).

  And this precursor solution was dripped on the board | substrate with which the 1st electrode was formed, the board | substrate was rotated at 3000 rpm, and the piezoelectric precursor film | membrane was formed (application | coating process). Next, it was dried at 180 ° C. for 2 minutes on a hot plate (drying process). Subsequently, degreasing was performed at 350 ° C. for 4 minutes (degreasing step). Next, the film was baked at 850 ° C. for 5 minutes with an RTA (Rapid Thermal Annealing) apparatus in an oxygen atmosphere to form a piezoelectric film (firing step). A series of steps of the coating step, the drying step, the degreasing step, and the firing step was repeated 10 times to form a piezoelectric layer 70 having a total thickness of 900 nm composed of ten piezoelectric layers.

  Thereafter, an iridium film (second electrode 80) having a thickness of 50 nm is formed as a second electrode 80 on the piezoelectric layer 70 by a sputtering method, and has a perovskite structure including Bi, Fe, Mn, Ba, and Ti. The piezoelectric element 300 having the composite oxide as the piezoelectric layer 70 was formed.

(Example 2)
The same procedure as in Example 1 was performed except that the firing temperature of the adhesion layer was set to 900 ° C.

(Comparative Example 1)
Example 1 was performed except that the piezoelectric layer was formed without providing the adhesion layer.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that an adhesion layer made of zirconium was provided instead of the adhesion layer of aluminum oxide.

(Test Example 1)
The piezoelectric film was removed with dilute hydrochloric acid, and the adhesion strength between the first electrode and the adhesion layer was measured using a Sebastian V-type strength tester (Phototechnica / Romulus IV).

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to what was mentioned above. For example, although the silicon single crystal substrate is illustrated as the flow path forming substrate 10, the present invention is not particularly limited thereto. For example, a material such as an SOI substrate or glass may be used.

  In addition, although an example of the orientation control layer has been given, for example, a buffer layer containing Bi and Mn can be used that is oriented on the (100) plane. Of course, if the amount of mutation can be secured, the orientation control layer is not necessarily provided.

  Moreover, the firing temperature of the piezoelectric layer is 750 to 850 ° C., and the amount of displacement can be sufficiently secured. Even in this case, the adhesion layer does not peel off the first electrode. Needless to say, even when the firing temperature is 750 ° C., film peeling does not occur in the same manner.

  The ink jet recording head of these embodiments constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 7 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 7, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting the ink supply means, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and the liquid ejecting ejects a liquid other than ink. Of course, it can also be applied to the head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  Further, the piezoelectric element according to the present invention is not limited to the piezoelectric element used in the liquid ejecting head, and can be used in other devices. Other devices include, for example, an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, a temperature-electric converter, a pressure-electric converter, a ferroelectric transistor, a piezoelectric transformer, and a filter for blocking harmful rays such as infrared rays. And filters such as an optical filter using a photonic crystal effect due to quantum dot formation and an optical filter using optical interference of a thin film. The present invention can also be applied to a piezoelectric element used as a sensor and a piezoelectric element used as a ferroelectric memory. Examples of the sensor using the piezoelectric element include an infrared sensor, an ultrasonic sensor, a thermal sensor, a pressure sensor, a pyroelectric sensor, and a gyro sensor (angular velocity sensor).

  I ink jet recording head (liquid ejecting head), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 15 communicating path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 40 compliance substrate , 50 elastic film, 55 insulator film, 56 adhesion layer, 60 first electrode, 65 orientation control layer, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric element

Claims (8)

  An adhesion layer provided on the substrate; a first electrode provided on the adhesion layer; a piezoelectric layer provided on the first electrode; and a second electrode provided on the piezoelectric layer. The actuator device is characterized in that the adhesion layer is made of aluminum oxide, and the piezoelectric layer is made of a complex oxide having a perovskite structure containing bismuth, iron, barium and titanium.   2. The actuator device according to claim 1, wherein the adhesion layer is formed by a CVD method or a chemical solution method.   3. The actuator device according to claim 1, wherein the adhesion layer is formed by a chemical solution method under a condition that a firing temperature is higher than a firing temperature of the piezoelectric layer.   The actuator device according to any one of claims 1 to 3, wherein the adhesion layer is formed by a chemical solution method at a firing temperature of 750 ° C or higher.   The actuator device according to any one of claims 1 to 4, wherein the piezoelectric layer is formed at a firing temperature of 850 ° C or higher.   The actuator device according to any one of claims 1 to 5, wherein the adhesion layer has a thickness of 10 to 50 nm.   A liquid ejecting head comprising the actuator device according to claim 1. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 7.

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