JP6179804B2 - Electromechanical transducer manufacturing method, electromechanical transducer, droplet ejection head, droplet ejection apparatus, and electromechanical transducer polarization processing apparatus - Google Patents

Description

  The present invention relates to an electromechanical conversion element manufacturing method and manufacturing apparatus, an electromechanical conversion element, a droplet discharge head including the electromechanical conversion element, and a droplet discharge apparatus including the droplet discharge head. is there.

  2. Description of the Related Art In recent years, an ink jet recording apparatus, which is a droplet discharge apparatus, is used as an image recording apparatus or an image forming apparatus such as a printer, a facsimile machine, and a copying apparatus. In this ink jet recording apparatus, a droplet discharge head is used as means for discharging a recording material made of a liquid such as ink. FIG. 1 is a cross-sectional view showing an example of a droplet discharge head. In FIG. 1, a droplet discharge head 10 includes a nozzle 11 that discharges ink droplets, and a pressure chamber 12 that communicates with the nozzle 11 (also referred to as an ink flow path, a pressurized liquid chamber, a pressure chamber, a discharge chamber, and a liquid chamber). ). Further, an electromechanical conversion element (piezoelectric element) 16 having an electromechanical conversion film 13, an upper electrode 14, and a lower electrode 15 that pressurizes ink in the pressurizing chamber 12 is provided. In addition, instead of the electromechanical conversion element 16, an electrothermal conversion element such as a heater, or one using a diaphragm forming a wall surface of the pressurizing chamber 12 and an electrode facing the diaphragm is known. Ink droplets are ejected from the nozzle 11 by pressurizing the ink in the pressurizing chamber 12 by the electromechanical transducer 16.

  The crystal of the piezoelectric body constituting the electromechanical conversion element (piezoelectric element) is in a state of random polarization as shown in FIG. 2A immediately after the piezoelectric element is manufactured. After that, by repeating the voltage application, the piezoelectric crystal becomes an aggregate of domains in which the directions of polarization are aligned as shown in FIG. The direction of polarization of the crystal of the piezoelectric body is preferably uniform from the beginning of use of the droplet discharge head in order to stabilize the polarization characteristics of the piezoelectric element and the properties of the droplet discharge head using the piezoelectric element. .

  Therefore, conventionally, there has been proposed a method of performing a polarization process for aligning the polarization direction of the piezoelectric element before the start of use of the droplet discharge head. For example, Patent Documents 1 and 2 disclose that a piezoelectric element that stabilizes the amount of displacement of the piezoelectric element with respect to the drive voltage by performing an aging process that applies an aging voltage to the piezoelectric element that is greater than the drive voltage during actual use. A manufacturing method is disclosed. Further, in Patent Document 3, a charge supply means for generating corona discharge is disposed so as to face the surface of the piezoelectric body through a gap, and the charge is supplied to the surface of the piezoelectric body by the corona discharge. A method is disclosed in which an electric field is generated in a piezoelectric body to perform polarization processing (polling processing).

  However, in the method of performing the aging process disclosed in Patent Documents 1 and 2 above, the aging voltage is applied by directly contacting the drive electrode constituting the piezoelectric element or the terminal electrode connected to the drive electrode. It is necessary to manufacture a probe card and a drive mechanism for driving the probe card, and the production efficiency is poor and the cost may be increased. In addition, when an aging voltage is applied to the corona electrode and a charge is injected into a plurality of drive electrodes or terminal electrodes arranged in a row, the charge concentrates on the drive electrode or terminal electrode at the end. There is a risk that uniform polarization of a plurality of piezoelectric elements cannot be performed.

  In the method disclosed in Patent Document 3, after the piezoelectric body is formed, the surface of the piezoelectric element is exposed before the subsequent post-process (interlayer film formation or lead wiring formation) is performed. It is necessary to perform polarization processing (polling processing). For this reason, a post-process (interlayer film formation or lead wiring formation) involving heat treatment at a high temperature (for example, a temperature exceeding 300 ° C.) is performed on the piezoelectric element that has been subjected to polarization processing (polling processing). Therefore, the piezoelectric element depolarizes due to the influence of the thermal history or the like in the subsequent process, and, for example, as shown in the PE hysteresis characteristic of FIG. There is a risk of depolarization returning to the state.

  The present invention has been made in view of the above problems, and its purpose is to reduce the variation in the polarization characteristics of the electromechanical transducer while preventing the occurrence of depolarization after the polarization treatment while improving the production efficiency. A method of manufacturing an electromechanical conversion element that can be performed, an electromechanical conversion element, a droplet discharge head including the electromechanical conversion element, and a droplet discharge apparatus including the droplet discharge head .

In order to achieve the above object, the invention of claim 1 is a method of manufacturing an electromechanical conversion element, comprising: forming a first drive electrode on a substrate or on a base film formed on the substrate. Forming a plurality of electromechanical conversion films independent from each other on the first drive electrode, and a plurality of second drive electrodes positioned on each of the plurality of electromechanical conversion films, Forming a first insulating protective film on the first drive electrode and the plurality of second drive electrodes; and a first electrically connected to the first drive electrode via a first wiring One terminal electrode, a plurality of second terminal electrodes electrically connected to each of the plurality of second drive electrodes via a second wiring, and electrically connected to the plurality of second terminal electrodes Forming a connected collective electrode on the first insulating protective film; Forming a second insulating protective film which is a film formed on the first wiring and the second wiring and which exposes the first terminal electrode, the second terminal electrode and the collecting electrode; And using a conductive member having a contact portion corresponding to the first terminal electrode, electrically contacting the contact portion of the conductive member with the first terminal electrode, and passing the conductive member through the conductive member. Te, the charges generated by the discharge can be injected into the first driving electrode, have a, a step of polarization process collectively the plurality of electromechanical conversion film, forming the second insulating protective film In this step, the collecting electrode is exposed to form the second insulating protective film, and the collecting electrode is grounded to the ground .

  According to the present invention, it is possible to reduce the variation in the polarization characteristics of the electromechanical transducer while preventing the occurrence of depolarization after the polarization process while improving the production efficiency.

FIG. 3 is a schematic sectional view of a droplet discharge head. (A), (b) is a schematic diagram of the polarization state of the piezoelectric crystal before and after voltage application. The hysteresis curve which shows the relationship between the electric field strength of a piezoelectric material, and the amount of polarization before a polarization process, after a polarization process, and after giving the thermal history over 300 [degreeC]. Sectional drawing of the electromechanical transducer which concerns on one Embodiment of this invention. It is explanatory drawing of a structure of the same electromechanical conversion element, (a) is sectional drawing, (b) is a top view. Explanatory drawing which discharges using a conductor plate and injects an electric charge by earth | grounding the electrode for an aging process to earth | ground. Explanatory drawing of a polarization process. It is a graph explaining a polarizability, (a) is a hysteresis loop about what has not performed polarization processing, and (b) is a hysteresis loop about what performed polarization processing. On a silicon substrate was deposited a titanium oxide film and a platinum film, a graph showing a SrRuO ₃ film X-ray diffraction measurement results of the samples was deposited. Sectional drawing which shows an example of a structure of a droplet discharge head. It is explanatory drawing of the state which individualized the electromechanical conversion film | membrane produced by Example 1, and the 2nd drive electrode by the etching, (a) is sectional drawing, (b) is a top view. FIG. 3 is an explanatory diagram of openings for connecting individual electrodes formed on the wafer according to the first embodiment. The perspective view of a polarization processing apparatus. It is explanatory drawing of the structure which inject | pours an electric charge into an electromechanical conversion element using a conductor plate, (a) is a top view, (b) is sectional drawing. Explanatory drawing of the electromechanical conversion element created by the comparative example 1. FIG. The graph which compared the electromechanical conversion element produced by Example 1, 2 and Comparative Example 1, 2, respectively. It is explanatory drawing explaining the cutting method of the electromechanical conversion element from a wafer, (a) is a top view, (b) is sectional drawing. It is explanatory drawing explaining the other cutting method of the electromechanical conversion element from a wafer, (a) is a top view, (b) is sectional drawing after a half cut, (c) is sectional drawing after complete cutting . FIG. 3 is a perspective view illustrating an example of a configuration of a droplet discharge device according to the present embodiment. The side view of the droplet discharge device. FIG. 9 is a top view of an electromechanical transducer according to Modification Example 1. It is explanatory drawing of the structure which inject | pours an electric charge into the electromechanical conversion element which concerns on the modification using a conductor plate, Comprising: (a) is a top view, (b) is sectional drawing.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings, but the present invention is not limited to these examples.
In the present embodiment, an example of a method for manufacturing an electromechanical transducer of the present invention and an electromechanical transducer obtained thereby will be described.

First, a configuration example of the electromechanical transducer according to this embodiment will be described.
FIG. 4 is a cross-sectional view schematically showing the electromechanical transducer according to this embodiment. As shown in FIG. 4, the electromechanical transducer (piezoelectric element) 30 has a first drive electrode 33 and a second drive electrode 35 laminated on a substrate 31 and a film formation diaphragm (base film) 32. It has a structure.

  Further, the structure of the electromechanical conversion element including the insulating protective film and the lead-out wiring will be described with reference to FIG. 5A is a cross-sectional view, FIG. 5B is a top view, and FIG. 5B is a perspective view of a part of the second insulating protective film so that the configuration of the piezoelectric element can be seen. It is described.

  In the electromechanical conversion element shown in FIG. 5, the first drive electrode 33, the electromechanical conversion film 34, and the second drive electrode 35 are provided on the substrate 31 and the film formation diaphragm 32 as in the case of FIG. 4. Are stacked. The electromechanical conversion film 34 and the second drive electrode 35 are individualized by etching after the second drive electrode is formed. The second drive electrode functions as an individual electrode, and the first drive electrode 33 functions as a common electrode for the individualized electromechanical conversion film 34 and the second drive electrode 35.

  On the first drive electrode 33 and the second drive electrode 35, a first insulating protective film 41 having a contact hole 45 is provided as shown in FIG. 5B. The contact hole 45 is provided so that the first drive electrode 33 and the second drive electrode 35 can be electrically connected to a first wiring 42 and a second wiring 43 described later. . Then, a first wiring 42 and a second wiring 43 are provided on the first insulating protective film 41, and through the contact hole 45 provided in the first insulating protective film 41 as described above. Thus, each is electrically connected to the first drive electrode 33 and the second drive electrode 35.

  Further, the common electrode and the individual electrode are protected by using the first drive electrode 33 and the first wiring 42 conducting to the common electrode as the common electrode, and the second driving electrode 35 and the second wiring 43 conducting to the individual electrode as the individual electrodes. A second insulating protective film 44 is formed. The second insulating protective film 44 is formed on the first wiring 42 and the second wiring 43 (and further on the first insulating protective film 41). The second insulating protective film 44 is provided with a plurality of openings 48 and 49 to expose the common electrode pad 46 as the first terminal electrode and the individual electrode pad 47 as the second terminal electrode. ing. Further, the second insulating protective film 44 is provided with an opening portion 50 for aging treatment, and the aging treatment electrode 51 as an aggregate electrode in which the second wirings 43 are electrically connected to each other is exposed.

  Among the plurality of pads, those prepared for the common electrode, that is, those connected to the common electrode are the common electrode pads 46, and those prepared for the individual electrodes, ie, those connected to the individual electrodes are individually The electrode pad 47 is used. As described above, these pads can be exposed to the outside by providing openings 48 and 49 in the second insulating protective film 44, for example.

The electromechanical transducer having the above-described configuration can be manufactured by performing the following steps (1) to (8).
(1) A step of forming the first drive electrode 33 on the substrate 31 or the base film (deposition diaphragm) 32. Here, the first drive electrode 33 may include an adhesion layer as described later.
(2) A step of forming an electromechanical conversion film 34 on the first drive electrode 33.
(3) A step of forming the second drive electrode 35 on the electromechanical conversion film 34.
(4) A step of individualizing the electromechanical conversion film 34 and the second drive electrode 35 by etching. By performing this process, the second drive electrode 35 is used as an individual electrode, and the first drive electrode 33 functions as a common electrode for the individual electromechanical conversion film 34 and the second drive electrode 35. become.
(5) A step of forming a first insulating protective film 41 on the first drive electrode 33 and the second drive electrode 35. In this process, the first insulating protective film 41 is used to electrically connect the first driving electrode 33 and the second driving electrode 35 to a first wiring 42 and a second wiring 43 which will be described later. A contact hole 45 can be formed.
(6) A step of forming the first wiring 42 and the second wiring 43 electrically connected to the first driving electrode 33 and the second driving electrode 35 on the first insulating protective film 41, respectively.
(7) Pads 46 and 47 and aging treatment electrodes 51 as a plurality of terminal electrodes for connection to the first wiring 42 or the second wiring 43 are formed on the first wiring 42 and the second wiring 43. Process.
(8) A step of forming a second insulating protective film 44 on the first wiring 42 and the second wiring 43. Here, the first wiring 42 and the second wiring 43 can be manufactured as separate processes in the above steps, but are preferably formed in the same process from the viewpoint of productivity.

  A plurality of pads (common electrode pad 46 and individual electrode pad 47) can be exposed to the outside by providing openings 48 and 49 in the second insulating protective film 44. Similarly, the aging electrode 51 can be exposed to the outside by providing the second insulating protective film 44 with the aging opening 50.

In the method of manufacturing the electromechanical transducer 30 according to this embodiment, as shown in FIG. 6, the aging electrode 51 is grounded to the ground, and the conductive plate 20 as a conductive member is connected to the common electrode pad 46 on the wafer. And corona discharge or glow discharge is performed on that portion. By this discharge, a charge amount of 1.0 × 10 ⁻⁸ [C] or more is generated, and the generated charge is injected through the pad, whereby the electromechanical conversion film 34 in the electromechanical conversion element 30 is polarized. Process.

  In the step of performing the polarization treatment, a charge amount equal to or more than the predetermined amount is generated by corona discharge or glow discharge, and the generated charge is injected into the electromechanical conversion film 34 through the common electrode pad 46. . At this time, it is preferable that the charge generated by corona discharge or glow discharge is negatively charged.

  For example, as shown in FIG. 7, when corona discharge is performed using a corona wire 52 as a discharge electrode, positive ions are generated by ionizing molecules in the atmosphere. The positive ions flow into the electromechanical conversion element 30 via the aging electrode 51 of the electromechanical conversion element 30 installed on the stage 53 and accumulate positive charges, and the polarization of the electromechanical conversion film 34 is accumulated. Processing is performed. In this embodiment, in order to inject charges into the first drive electrode 33, negative ions are generated and injected with the polarity reversed. Further, in addition to the corona wire 52, a grid electrode may be provided to perform corona discharge.

Here, considering the charge amount Q required for the polarization treatment, it is preferable that a charge amount of 1.0 × 10 ⁻⁸ [C] or more is accumulated (generated), and 4.0 × 10 ⁻⁸ [C]. More preferably, the above charge amount is accumulated (generated). If the amount of charge Q is less than the above value, the electromechanical conversion film (for example, PZT film) 34 may not be sufficiently polarized, and sufficient characteristics can be obtained for displacement degradation after continuous driving as a piezoelectric actuator. This is because it may not be possible.

  The state of the polarization process can be determined from the PE hysteresis loop.

  FIG. 8A shows the hysteresis loop measured for the sample not subjected to the polarization processing described in FIG. 2, and FIG. 8B shows the hysteresis loop measured for the polarization treatment.

  As shown in FIGS. 8A and 8B, a hysteresis loop is measured by applying an electric field strength of ± 150 [kV / cm]. The initial polarization at 0 [kV / cm] is Pini, and the polarization at 0 [kV / cm] when the voltage is returned to 0 [kV / cm] after applying a voltage of +150 [kV / cm] is Pr.

At this time, the difference between Pr and Pini, that is, the value of Pr−Pini is defined as the polarizability, and whether the polarization state is good or bad can be determined from this polarizability. Here, as shown in FIG. 8B, the polarizability Pr-Pini is preferably 10 [μC / cm ² ] or less, and more preferably 5 [μC / cm ² ] or less. preferable. This is because when a piezoelectric actuator is formed using an electromechanical conversion film (for example, a PZT film) 34 that does not satisfy this value, sufficient characteristics may not be obtained with respect to displacement deterioration after continuous driving.

That is, the electromechanical transducer 30 obtained by the manufacturing method described above measures a hysteresis loop by applying an electric field strength of ± 150 [kV / cm]. The polarization at 0 [kV / cm] at the start of measurement is Pini, and the polarization at 0 [kV / cm] when the voltage is returned to 0 [kV / cm] after applying a voltage of +150 [kV / cm] is Pr. To do. In this case, the difference between Pr and Pini is preferably 10 [μC / cm ² ] or less, and more preferably 5 [μC / cm ² ] or less.

  Further, in the electromechanical conversion element 30 obtained by the manufacturing method described above, the relative dielectric constant of the electromechanical conversion film 34 is preferably 600 or more and 2000 or less.

  Below, the material and construction method which comprise the electromechanical conversion element of this embodiment are demonstrated concretely.

(substrate)
The material of the substrate 31 is not particularly limited, but a silicon single crystal substrate is preferably used. The thickness is preferably 100 to 600 [μm].

  There are three types of plane orientation of the silicon single crystal substrate, (100), (110), and (111), but (100) and (111) are generally widely used in the semiconductor industry. In this configuration, a silicon single crystal substrate having a (100) plane orientation can be preferably used. In the electromechanical transducer 30 in the present embodiment, a single crystal substrate having a (110) plane orientation can also be preferably used.

  When the pressure chamber shown in FIG. 1 is manufactured on the substrate 31, the silicon single crystal substrate is generally processed by using etching. In this case, anisotropic etching is used as an etching method. It is common.

Anisotropic etching utilizes the property that the etching rate differs with respect to the plane orientation of the crystal structure. For example, in anisotropic etching immersed in an alkaline solution such as KOH, the (111) plane has an etching rate of about 1/400 compared to the (100) plane. Accordingly, a structure having an inclination of about 54 [°] can be produced in the plane orientation (100), whereas a deep groove can be dug in the plane orientation (110), so that the arrangement density can be maintained while maintaining rigidity. Can be high. For this reason, when producing a pressure chamber etc. using anisotropic etching, it is also possible to use a silicon single crystal substrate having a (110) plane orientation. However, in this case, SiO ₂ which is a mask material may be etched, so that it is desirable to use this in consideration.

(Undercoat (diaphragm))
Under the force generated by the electro-mechanical conversion film 13 as shown in FIG. 1, the base film (diaphragm) 17 is deformed displaced to eject ink droplets of the pressure chamber 12. Therefore, it is preferable that the base film 17 has a predetermined strength.

The material for the base film 17 as long as it can eject ink droplets of the pressure chamber 12 is deformed displaced, but can be arbitrarily selected depending on the required durability, for example, Si , SiO ₂ , Si ₃ N ₄ can be used. When these materials are used, they can be manufactured by a CVD (Chemical Vapor Deposition) method.

Further, it is preferable to select a material close to the linear expansion coefficient of the first drive electrode (lower electrode) 15 and the electromechanical conversion film 13 as the base film (vibration plate) 17. In particular, as the electromechanical conversion film 13, since PZT is generally used as a material, a film having a linear expansion coefficient close to 8 × 10 ⁻⁶ [1 / K] of PZT is preferable. Specifically, the material preferably has a linear expansion coefficient in the range of 5 × 10 ⁻⁶ [1 / K] to 10 × 10 ⁻⁶ [1 / K], and more preferably 7 × 10 ^−6. A material having a linear expansion coefficient in the range of [1 / K] to 9 × 10 ⁻⁶ [1 / K] is more preferable.

  In this case, specific materials include aluminum oxide, zirconium oxide, iridium oxide, ruthenium oxide, tantalum oxide, hafnium oxide, osmium oxide, rhenium oxide, rhodium oxide, palladium oxide, and compounds thereof. These materials can be manufactured by a spin coater using a sputtering method or a sol-gel method.

The film thickness is not particularly limited, but is preferably in the range of 0.1 [μm] to 10 [μm], and more preferably in the range of 0.5 [μm] to 3 [μm]. May work in this range is smaller than a pressure chamber 12 as shown in FIG. 1 is difficult, the range larger than the base film 17 is less likely to deform displacement, there are cases where ejection of ink droplets becomes unstable Because.

(First drive electrode)
For example, the first drive electrode 15 shown in FIG. 1 is not particularly limited, but is preferably made of a metal or a metal and an oxide. Specifically, the first drive electrode 15 can be composed of a metal electrode film, for example. Moreover, it can also be comprised from a metal electrode film and an oxide electrode film.

  Even when the first drive electrode 15 is made of any material, it is preferable to devise an adhesive layer between the diaphragm 17 and the metal film so as to suppress peeling and the like. Details of the metal electrode film and oxide electrode film including the adhesion layer are described below.

The adhesion layer can be obtained, for example, by forming a metal film and then oxidizing (thermally oxidizing) it by an RTA method using an RTA (Rapid Thermal Annealing) apparatus to form an oxide film. Conditions for the oxidation (thermal oxidation) are not particularly limited, and can be selected depending on the material of the metal film to be used. For example, it can be formed by thermally oxidizing a metal film at 650 to 800 [° C.] for 1 to 30 minutes in an O ₂ atmosphere.

  The metal film can be formed by sputtering, for example. As a material for the metal film, materials such as Ti, Ta, Ir, and Ru can be preferably used, and among these, Ti can be preferably used.

  The metal oxide film may be formed by reactive sputtering, but a thermal oxidation method at a high temperature of the metal film is desirable. This is because, when manufacturing by reactive sputtering, for example, a substrate such as a silicon substrate needs to be heated together at a high temperature, so that a special sputtering chamber configuration is required, which is not preferable in terms of cost. In addition, the crystallinity of the metal oxide film is improved by the oxidation by the RTA apparatus than by the oxidation by a general furnace. This is explained by taking a titanium film as an example. According to oxidation by a normal heating furnace, a titanium film that is easily oxidized forms a number of crystal structures at a low temperature, so that it is necessary to break it once. On the other hand, in the oxidation by the RTA method having a high temperature rising rate, it is not necessary to go through such a process, and it becomes possible to form a good crystal.

  The thickness of the adhesion layer is not particularly limited, but is preferably in the range of 10 [nm] to 50 [nm], and more preferably in the range of 15 [nm] to 30 [nm]. When the film thickness is thinner than the above range, the adhesion between the diaphragm and the first drive electrode may be deteriorated. Further, if the film thickness is larger than the above range, the crystal quality of the first drive electrode film formed thereon may be affected. For this reason, it is preferable to select the said range.

  Conventionally, platinum having high heat resistance and low reactivity can be used as the metal material of the metal electrode film. In addition, since platinum may not have sufficient barrier properties with respect to lead, platinum group elements such as iridium and platinum-rhodium, and alloys thereof can also be used.

In addition, when platinum is used as the metal material of the metal electrode film, it is preferable that the adhesion layer is laminated first because adhesion to the base (particularly SiO ₂ ) is poor.

  The method for producing the metal electrode film is not particularly limited, but vacuum film formation such as sputtering or vacuum deposition can be used.

  The thickness of the metal electrode film may be selected according to the required performance, and is not limited, but is preferably 80 [nm] to 200 [nm], for example, 100 [nm] to 150 [Nm] is more preferable. When the thickness is smaller than the above range, it may not be possible to supply a sufficient current as the common electrode, and a problem may occur when ink is ejected. In addition, when the thickness is larger than the above range, particularly when an expensive material of a platinum group element is used as the metal material of the metal electrode film, there is a problem in terms of cost. In particular, when platinum is used as the metal material, the surface roughness increases when the film thickness is increased. Then, when a defect occurs that affects the surface roughness and crystal orientation of the film (for example, an oxide electrode film or an electromechanical conversion film) to be formed thereon and sufficient displacement cannot be obtained for ink ejection. There is.

As a material for the oxide electrode film, it is preferable to use strontium ruthenate (SrRuO ₃ , hereinafter also simply referred to as “SRO”). The material obtained by replacing a part of strontium ruthenate, specifically, SrxA1-xRuyB1-yO ₃ (wherein, A is Ba, Ca, B is Co, Ni, x, y = 0~0.5) The material represented by can also be preferably used.

  The oxide electrode film can be formed by sputtering, for example. Although the sputtering conditions are not limited, the film quality of the oxide film changes depending on the sputtering conditions, and can be selected according to the required crystal orientation.

  For example, the electromechanical conversion film 34 to be described later is preferably oriented in the (111) plane orientation as its crystallinity in order to suppress deterioration of displacement characteristics when continuously operated. In order to obtain such an electromechanical conversion film 34, it is preferable that the oxide electrode film disposed in the lower layer is also oriented in the (111) plane direction. For this reason, the oxide electrode film is preferably preferentially oriented in the (111) plane orientation.

  Then, in order to obtain a film preferentially oriented in the (111) plane orientation with respect to the oxide electrode film, it is preferable to heat the substrate to 500 [° C.] or higher, and form the oxide electrode film thereon by sputtering.

  Moreover, when providing a metal electrode film in the lower layer of an oxide electrode film, it is preferable that this metal electrode film consists of a platinum film. Moreover, it is preferable that it is oriented in the (111) plane orientation as the plane orientation. This is because it is easy to obtain an oxide electrode film formed thereon that is preferentially oriented in the (111) plane orientation.

  For example, Patent Document 4 states that the SRO film is deposited at room temperature and then thermally oxidized at the crystallization temperature by RTA treatment. In this case, the SRO film is sufficiently crystallized and a sufficient value is obtained as a specific resistance as an electrode. However, as the crystal orientation of the film, (110) is likely to be preferentially oriented. When a PZT film is formed, this PZT film is also easily (110) oriented. For this reason, when forming the SRO film in the present embodiment, it is preferable to form the film under the above film forming conditions.

Here, for example, when a platinum film oriented in the (111) plane direction is used as a metal electrode film, and an SrRuO ₃ film as an oxide electrode film is formed thereon, the crystallinity of the oxide electrode is measured by X-ray diffraction measurement. The method of evaluation will be described.

Since Pt and SrRuO ₃ have close lattice constants, in the θ-2θ measurement in the normal X-ray diffraction measurement, the 2θ positions of the (111) plane of the SRO film and the (111) plane of Pt overlap and are difficult to discriminate. However, when Pt is tilted to Psi = 35 [°] due to the extinction law, the diffraction lines cancel each other at a position where 2θ is about 32 [°], and the diffraction intensity of Pt cannot be seen. Therefore, it is possible to confirm whether the SRO is preferentially oriented in the (111) plane orientation by inclining the Psi direction by about 35 [°] and judging from the peak intensity where 2θ is about 32 [°].

In FIG. 9, after forming a titanium oxide film as an adhesion layer on a silicon substrate, a platinum film oriented in the (111) plane orientation is formed, and the substrate is heated to, for example, 550 [° C.]. The X-ray diffraction measurement result of the sample on which the SrRuO ₃ film is formed by sputtering is shown.

  FIG. 9 shows data when 2θ = 32 [°] is fixed and Psi is changed. When Psi = 0 [°], almost no diffraction intensity is observed in the diffraction line on the (110) plane of SRO, and the diffraction intensity is observed in the vicinity of Psi = 35 [°]. ) It can be confirmed that the preferred orientation is in the plane orientation. In addition, from this result, it was confirmed that SRO was preferentially oriented in the (111) plane direction for those produced under the present film forming conditions.

  Further, when the SRO film prepared by performing the RTA process after forming the SRO film described above at room temperature was evaluated in the same manner, the diffraction intensity of SRO (110) was found when Psi = 0 [°]. It was seen.

  It was estimated how much the displacement after driving was degraded compared to the initial displacement when continuously operating as a piezoelectric actuator. According to this estimate, the orientation of the electromechanical conversion film (for example, PZT film) 34 has a great influence, and (110) may be insufficient in suppressing displacement deterioration. For this reason, as described above, the oxide electrode film is preferably oriented in the (111) plane orientation.

The surface roughness of the SrRuO ₃ film used for the oxide electrode is preferably 4 [nm] or more and 15 [nm] or less, and more preferably 6 [nm] or more and 10 [nm] or less. In addition, about the surface roughness here, the surface roughness (average roughness) measured by AFM is meant.

The surface roughness of the SrRuO ₃ film affects the film formation temperature, and when the substrate is heated from room temperature to 300 [° C.], the surface roughness is very small and becomes 2 [nm] or less. In this case, the surface roughness is very small and flat, but the crystallinity of the SrRuO ₃ film may not be sufficient. Thus, when the crystallinity of the SrRuO ₃ film is not sufficient, a piezoelectric actuator having an electromechanical conversion film (for example, a PZT film) to be formed thereafter cannot obtain sufficient characteristics with respect to initial displacement or displacement deterioration after continuous driving. .

Thus, considering the film formation conditions, the surface roughness obtained without deteriorating the crystallinity of the SrRuO ₃ film is considered to be within the above range. Therefore, the above range is preferable.

When it deviates from the above range, the crystallinity of the SrRuO ₃ film may be deteriorated, and the withstand voltage of the electromechanical conversion film to be formed thereafter is deteriorated and may be liable to leak.

In order to obtain the SrRuO ₃ film having the crystallinity and the surface roughness as described above, the film formation condition (temperature) is 500 [° C.] to 700 [° C.], preferably 520 [° C.] to 600 It is preferable to heat the substrate in the range of [° C.] and form a film by sputtering.

  The composition ratio of Sr and Ru after film formation is not particularly limited and is selected depending on required conductivity, etc., but Sr / Ru is preferably 0.82 or more and 1.22 or less. . This is because if it is out of the above range, the specific resistance increases, and sufficient conductivity as an electrode may not be obtained.

  Furthermore, the thickness of the SRO film as the oxide electrode is preferably 40 [nm] or more and 150 [nm] or less, and more preferably 50 [nm] or more and 80 [nm] or less. If the thickness is less than the above range, sufficient characteristics may not be obtained for initial displacement and displacement deterioration after continuous driving. Moreover, it becomes difficult to obtain a function as a stop etching layer for suppressing over-etching of the electromechanical conversion film. Further, if the film thickness exceeds the above-mentioned film thickness range, the dielectric strength voltage of the PZT formed thereafter is deteriorated and it may be likely to leak.

The specific resistance of the oxide electrode is preferably 5 × 10 ⁻³ [Ω · cm] or less, and more preferably 1 × 10 ⁻³ [Ω · cm] or less. If it exceeds this range, sufficient contact resistance cannot be obtained at the interface with the first wiring, and sufficient current cannot be supplied as a common electrode, which may cause problems when ink is ejected. It is.

(Electromechanical conversion membrane)
The electromechanical conversion film 34 can be used as long as it has a piezoelectric property, and is not particularly limited. For example, PZT that is widely used can be preferably used. PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ), and the characteristics differ depending on the ratio, but the ratio is not limited, and the required piezoelectric performance, etc. Can be selected. Among them, the ratio (molar ratio) of PbZrO ₃ and PbTiO ₃ is 53:47, and when expressed by the chemical formula, it is also indicated as PZT (PZT (53/47)) represented by Pb (Zr0.53, Ti0.47) O _3. ) Can be preferably used because it exhibits particularly excellent piezoelectric characteristics.

  Barium titanate can also be used as a material other than PZT. In this case, it is possible to prepare a barium titanate precursor solution by using barium alkoxide and a titanium alkoxide compound as starting materials and dissolving them in a common solvent.

The PZT and barium titanate are represented by the general formula ABO ₃ . In addition to PZT and barium titanate, a composite oxide mainly composed of a composite oxide represented by ABO ₃ (A = Pb, Ba, Sr, B = Ti, Zr, Sn, Ni, Zn, Mg, Nb) is used. Can be used.

Further, a composite oxide in which Pb at the A site is partially substituted with Ba or Sr, such as (Pb1-x, Bax) (Zr, Ti) O ₃ , (Pb1-x, Srx) (Zr, Ti) O ₃ Can also be used. A divalent element can be used as an element used for substitution. When a heat treatment is performed when an electromechanical conversion film is formed by substituting a part of Pb with a divalent element, lead can be used. There is an effect of reducing characteristic deterioration due to evaporation.

  A method for producing the electromechanical conversion film 34 is not particularly limited, but for example, it can be produced by a spin coater using a sputtering method or a sol-gel method. Then, after the film formation, a desired pattern can be obtained by patterning by a pattern formation method using a photolithography technique and an etching technique (hereinafter referred to as “lithoetch method”).

A case where the electromechanical conversion film 34 made of PZT is manufactured by a sol-gel method will be described as an example.
PZT precursor solution is prepared by using lead acetate, zirconium alkoxide, and titanium alkoxide compound as starting materials, using methoxyethanol as a common solvent, and dissolving the above starting materials in a common solution so as to have a predetermined ratio to obtain a uniform solution. To do. Since the metal alkoxide compound is easily hydrolyzed by moisture in the atmosphere, an appropriate amount of a stabilizer such as acetylacetone, acetic acid or diethanolamine can be added to the precursor solution as a stabilizer. In addition, since the lead component may evaporate during heat treatment in the film forming process, it can be added in a larger amount than the stoichiometric ratio.

  When a PZT film is obtained on the entire surface of the base substrate, the PZT film can be obtained by forming a coating film by a solution coating method such as spin coating and performing heat treatments such as solvent drying, thermal decomposition, and crystallization. Since transformation from a coating film to a crystallized film involves volume shrinkage, the precursor concentration should be adjusted so that a film thickness of 100 [nm] or less can be obtained in one step in order to obtain a crack-free film. Preferably, a PZT film having a desired film thickness can be obtained by repeatedly performing the film forming process.

  In the case of a barium titanate film, for example, a barium titanate precursor solution is prepared by using barium alkoxide and a titanium alkoxide compound as starting materials and dissolving them in a common solvent. And using this, for example, it is possible to form a film by the sol-gel method in the same procedure as in the case of PZT.

  The film thickness of the electromechanical conversion film 34 is not limited and may be selected according to the required piezoelectric characteristics, but is preferably 0.5 [μm] or more and 5 [μm] or less, More preferably, it is 1 [μm] or more and 2 [μm] or less. This is because if the thickness is smaller than the above range, sufficient displacement may not be generated when used as a piezoelectric actuator. On the other hand, if the thickness is larger than the above range, a number of layers are deposited in the manufacturing process, so that the number of processes increases and the process time becomes longer.

  The relative dielectric constant of the electromechanical conversion film 34 is preferably 600 or more and 2000 or less, and more preferably 1200 or more and 1600 or less. If the relative permittivity is smaller than the range, sufficient displacement characteristics may not be obtained when used as a piezoelectric actuator. Further, when the relative permittivity is larger than the range, there may be a problem in that the polarization process is not sufficiently performed and sufficient characteristics cannot be obtained for the displacement degradation after continuous driving.

(Second drive electrode)
Although it does not specifically limit as the 2nd drive electrode 35, It is preferable that it consists of a metal or an oxide, and a metal. Specifically, the second drive electrode 35 can be composed of, for example, a metal electrode film. Moreover, it can also comprise from a metal electrode film and an oxide electrode film.

Details of the oxide electrode film and the metal electrode film are described below.
The material or the like of the oxide electrode film is the same as that described for the oxide electrode film of the first drive electrode. The thickness of the oxide electrode film is preferably 20 [nm] or more and 80 [nm] or less, and more preferably 40 [nm] or more and 60 [nm] or less. If the thickness is less than this range, sufficient characteristics may not be obtained for the initial displacement and displacement deterioration characteristics. If this range is exceeded, the dielectric strength of the electromechanical conversion film will be very poor and leakage will occur. It is because it may become easy to do.

  The material of the metal electrode film is the same as that described for the metal electrode film of the first drive electrode. The film thickness of the metal electrode film is preferably 30 [nm] to 200 [nm], and more preferably 50 [nm] to 120 [nm]. This is because if the thickness is smaller than this range, a sufficient current cannot be supplied as an individual electrode, and a problem may occur when ink is ejected. When the thickness is larger than this range, there is a problem in that the cost increases when an expensive platinum group element material is used as the material of the metal electrode film. Further, in the case of using platinum as a material, the surface roughness increases as the film thickness increases, and when the second wiring is formed through the first insulating protective film, film peeling, etc. This is because there is a case where the above-mentioned trouble is likely to occur.

(First insulating protective film)
The first insulating protective film 41 preferably has a function of preventing damage to the piezoelectric element due to the film forming / etching process and preventing moisture in the air from permeating. Therefore, the material is preferably a dense inorganic material. In the case of organic materials, it is necessary to increase the film thickness in order to obtain sufficient protection performance. However, if the insulating film is made thick, the vibration displacement of the diaphragm is hindered and the liquid droplet ejection head has a low ejection performance. This is because there is a case of becoming.

In order to obtain high protection performance with a thin film, it is preferable to use an oxide, nitride, or carbide thin film, but it has high adhesion to electrode materials, electromechanical conversion film materials, and diaphragm materials that form the base of insulating films. It is preferable to select the material. Specifically, the first insulating protective film 41 is preferably made of at least one inorganic film selected from, for example, an alumina film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film. More _{specifically, Al 2 O 3, ZrO 2} , Y 2 O 3, Ta 2 O 3, an oxide film used in the ceramic material, such as TiO ₂ can be cited as examples. These films have good adhesion, hard films, and excellent wear resistance and cost performance.

  Further, the film formation method of the first insulating protective film 41 is also preferably a film formation method with a low possibility of damaging the piezoelectric element. For example, an evaporation method, an atomic layer deposition (ALD) method, or the like can be preferably used, and an ALD method with a wide range of materials that can be used is more preferably used. In particular, by using the ALD method, a thin film having a very high film density can be manufactured, and damage during the process can be suppressed.

  The plasma CVD method in which a reactive gas is turned into plasma and deposited on the substrate, and the sputtering method in which the film is formed by causing the plasma to collide with the target material and flying may cause damage to the piezoelectric element, compared with the vapor deposition method and the ALD method. It is not preferable because it is expensive.

  The film thickness of the first insulating protective film 41 may be a thin film having a sufficient thickness for protecting the piezoelectric element and may be as thin as possible so as not to disturb the displacement of the diaphragm. It is not limited. For example, the thickness of the first insulating protective film is preferably in the range of 20 [nm] to 100 [nm]. When the thickness is larger than 100 [nm], the displacement of the vibration plate is reduced, so that a droplet discharge head (inkjet head) with low discharge efficiency may be obtained. On the other hand, when the thickness is less than 20 [nm], the function as a protective layer of the piezoelectric element may not be sufficient, and the performance of the piezoelectric element may be deteriorated.

  Further, a configuration in which another layer is provided as the first insulating protective film 41 to form two layers is also conceivable. In this case, for example, the second insulating film may be thickened to open the second insulating film in the vicinity of the second drive electrode portion so as not to inhibit the vibration displacement of the diaphragm.

Arbitrary oxides, nitrides, carbides, or composite compounds thereof can be used for the second insulating protective film. For example, SiO ₂ that is generally used in semiconductor devices can be used.

  Arbitrary methods can be used as a method for forming the second insulating protective film, and examples thereof include a CVD method and a sputtering method. It is preferable to use a CVD method capable of forming an isotropic film in consideration of the step coverage of the pattern forming portion such as the electrode forming portion.

  The film thickness of the second insulating protective film is preferably selected so that the dielectric breakdown is not caused by the voltage applied between the common electrode and the individual electrode wiring. That is, it is preferable to set the electric field strength applied to the insulating film within a range not causing dielectric breakdown. Furthermore, in consideration of the surface property of the base of the second insulating film, pinholes, etc., the film thickness is preferably 200 [nm] or more, and more preferably 500 [nm] or more.

(First and second wiring)
The first wiring 42 and the second wiring 43 are electrically connected to the first driving electrode 33 and the second driving electrode 35, respectively, and are formed on the first insulating protective film 41. .

  The material of the first wiring 42 and the second wiring 43 is not particularly limited, and may be selected according to required performance. For example, Ag alloy, Cu, Al, Al alloy, It is preferably made of at least one metal selected from Au, Pt, and Ir. These metals can form a low-resistance and durable electrode on the substrate.

  As a method for manufacturing the first wiring 42 and the second wiring 43, for example, a method of manufacturing by using a sputtering method or a spin coating method and then obtaining a desired pattern by the above-described lithoetching method or the like is preferably used. it can.

  The film thicknesses of the first wiring 42 and the second wiring 43 are preferably 0.1 [μm] to 20 [μm], and more preferably 0.2 [μm] to 10 [μm]. If the film thickness is smaller than the above range, the resistance increases, and a sufficient current cannot flow through the electrode, and the droplet discharge head may become unstable when the droplet discharge head is used. On the other hand, if the film thickness is larger than the above range, the process time becomes long, which may cause a problem in productivity.

  Further, a portion of the first wiring 42 exposed from the opening (contact hole portion) 48 becomes a common electrode pad 46. In addition, a portion of the second wiring 43 exposed from the opening (contact hole portion) 49 becomes an individual electrode pad 47. The contact resistance at the openings (contact hole portion, 10 [μm] × 10 [μm]) 48 and 49 of these pads 46 and 47 is preferably 10 [Ω] or less as the contact resistance of the common electrode pad 46. The contact resistance of the individual electrode pad 47 is preferably 1 [Ω] or less. Furthermore, the contact resistance of the common electrode pad 46 is more preferably 5 [Ω] or less, and the contact resistance of the individual electrode pad 47 is more preferably 0.5 [Ω] or less. This is because when the contact resistance at the openings (contact hole portions) 48 and 49 of the pads 46 and 47 exceeds the above range, a sufficient current cannot be supplied. This is because problems may occur when ejecting droplets.

  Further, the aging electrode 51 may be formed integrally with the second wiring 43. The aging electrode 51 is exposed from the aging opening 50 formed in the second insulating protective film 44. The contact resistance of the aging electrode 51 is preferably 1 [Ω] or less, and the contact resistance of the aging electrode 51 is more preferably 0.5 [Ω] or less. This is because if the contact resistance at the aging electrode 51 exceeds the above range, a sufficient current cannot be supplied, and there is a possibility that sufficient charge injection cannot be performed on the electromechanical conversion film 34 during the polarization process. It is.

(Second insulating protective film)
The second insulating protective film 44 functions as a passivation layer having a function of a protective layer for individual electrode wiring and common electrode wiring.

  As shown in FIG. 5A, the individual electrode and the common electrode are covered except for the individual electrode lead portion and the common electrode lead portion (not shown). By providing the second insulating protective film 44 in this way, inexpensive Al or an alloy material containing Al as a main component can be used as the electrode material. As a result, a low-cost and highly reliable ink jet head can be obtained.

  As a material of the second insulating protective film 44, any inorganic material or organic material can be used, but a material having low moisture permeability is preferably used.

  As the inorganic material, for example, an oxide, nitride, carbide, or the like can be used, and as the organic material, polyimide, an acrylic resin, a urethane resin, or the like can be used. However, in the case of an organic material, it is necessary to form a thick film, which is not suitable for patterning described later. Therefore, it is more preferable to use an inorganic material that can exhibit a wiring protection function with a thin film.

Therefore, the second insulating protective film 44 is preferably at least one inorganic film selected from an alumina film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film. In particular, the use of Si ₃ N ₄ as the second insulating protective film on the Al wiring is a technology that has a proven record in semiconductor devices. Therefore, it is preferable to adopt the same configuration also in this embodiment.

  The thickness of the second insulating protective film 44 is preferably 200 [nm] or more, and more preferably 500 [nm] or more. This is because, when the film thickness is small, a sufficient passivation function cannot be exhibited, and therefore disconnection due to corrosion of the wiring material may occur, which may reduce the reliability of the electromechanical conversion element.

  Further, a structure having openings on the piezoelectric element and the surrounding diaphragm is preferable. This is the same reason for providing the opening 49 in the vicinity of the individual electrode pad 47 on the first insulating protective film 41 described above. Thereby, it can be set as a highly efficient and highly reliable electromechanical conversion element. Further, for example, a highly efficient and highly reliable droplet discharge head or inkjet head using the electromechanical transducer 30 can be obtained.

  Since the piezoelectric elements are protected by the first insulating protective film 41 and the second insulating protective film 44, the openings 48 and 49 can be formed by photolithography and dry etching.

The second insulating protective film 44 is provided with a plurality of pads (a common electrode pad 46 and an individual electrode pad 47). The area of these pads is preferably 2500 [μm ² ] or more. Further, it is more preferably 30000 [μm ² ] or more. This is because when the value is less than this value, sufficient polarization processing cannot be performed, or sufficient characteristics may not be obtained for displacement deterioration after continuous driving.

  A method for forming the plurality of pads (the common electrode pad 46 and the individual electrode pad 47) is not particularly limited. For example, the pads can be formed by using the litho-etching method described above.

(Conductor plate)
The conductor plate 20 has a function of injecting electric charges generated by corona discharge or glow discharge into the electromechanical transducer 30.

  As shown in FIG. 7, the conductor plate 20 is composed of a main body plate portion 20a and a protruding contact portion 20b. The contact portion 20b of the conductor plate 20 is connected to the opening of the common electrode pad 46, Corona discharge or glow discharge is performed on that part.

  As shown in FIG. 6, the area of the conductor plate 20 is preferably equal to the substrate 31 on which the electromechanical transducer 30 is present, and more preferably larger than that. This is because, if the area of the conductor plate 20 is smaller than the above area, the electric charge generated by the corona discharge is injected into the individual electrode pad 47 and the like, and the strength of this electric field is reduced, and the desired effect in the polarization treatment is achieved. It is because there is a possibility that cannot be obtained.

  The material constituting the conductor plate 20 is preferably the same material as the common electrode pad 46 and the individual electrode pad 47 (the first wiring 42 and the second wiring 43). That is, the material constituting the conductor plate 20 is a metal electrode material selected from the same kind of Ag alloy, Cu, Al, Au, Pt, and Ir as the first wiring 42 and the second wiring 43. Is preferred.

Further, the surface of the lower side in FIG. 7 of the conductor plate 20, a first plurality of contact portions 20b protruding corresponding to the position and number of the pads 4 6 for connection to the wiring 4 2 as described above Is provided. The height of these contact portions 20b is, for example, 1 [mm]. When the polarization process is performed, these contact portions 20b are connected to the common electrode pad 46 connected to the first wiring 42 to inject charges.

  According to the manufacturing method of the electromechanical conversion element 30 of the present embodiment described above, the polarization process can be performed on the piezoelectric elements at the wafer level. Further, when the electromechanical conversion element 30 obtained by this manufacturing method is a droplet discharge head, the electromechanical conversion element 30 exhibits a stable displacement with respect to a predetermined drive voltage, and maintains a good droplet discharge characteristic. In addition, it is possible to obtain stable droplet discharge characteristics.

  Specifically, as shown in FIG. 1, a nozzle 11 that discharges droplets, a pressurizing chamber 12 that communicates with the nozzle 11, and a discharge driving unit that pressurizes the liquid in the pressurizing chamber 12. A liquid droplet ejection head 10 is provided. In the droplet discharge head 10 according to the present embodiment, as a discharge drive unit, a part of the wall of the pressurizing chamber 12 is configured by a vibration plate, and the above-described electromechanical conversion element is disposed on the vibration plate. is there.

  According to this droplet discharge head 10, since the above-described electromechanical conversion element is used, a stable displacement amount with respect to a predetermined drive voltage can be exhibited, droplet discharge characteristics can be maintained well, and stable droplet discharge can be achieved. Characteristics can be obtained.

  In the present embodiment, the droplet discharge head composed of one nozzle has been described. However, the present invention is not limited to such a configuration, and a configuration including a plurality of droplet discharge heads as shown in FIG. it can. In FIG. 10, a plurality of droplet discharge heads of FIG. 1 are arranged in series, and the same numbers are assigned to the same members.

  Moreover, although description about a liquid supply means, a flow path, fluid resistance, etc. was abbreviate | omitted, the incidental equipment which can be provided in a droplet discharge head can be provided naturally.

[Example 1]
Hereinafter, a more specific manufacturing method of the electromechanical transducer will be described with reference to examples. However, the present invention is not limited to these examples.

  First, a thermal oxide film (film thickness: 1 [μm]) was formed on a 6-inch silicon wafer.

Next, a first drive electrode was formed. Specifically, first, as an adhesion film, a titanium film (film thickness: 30 [nm]) was formed by a sputtering apparatus, and then thermally oxidized at 750 [° C.] using RTA. Subsequently, a platinum film (film thickness 100 [nm]) was formed as a metal film, and an SrRuO ₃ film (film thickness 60 [nm]) was formed as an oxide film by sputtering. Film formation was performed at a substrate heating temperature of 550 [° C.] during the sputtering film formation.

  Next, an electromechanical conversion film was formed. Specifically, a solution having a molar ratio of Pb: Zr: Ti = 114: 53: 47 was prepared, and a film was formed by spin coating.

  For the synthesis of a specific precursor coating solution, lead acetate trihydrate, isopropoxide titanium, and normal propoxide zirconium were used as starting materials. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. The lead amount is excessive with respect to the stoichiometric composition. This is to prevent crystallinity deterioration due to so-called lead loss during heat treatment.

  Isopropoxide titanium and normal propoxide zirconium were dissolved in methoxyethanol, the alcohol exchange reaction and the esterification reaction were advanced, and the PZT precursor solution was synthesized by mixing with the methoxyethanol solution in which the lead acetate was dissolved. The PZT concentration in the synthesized PZT precursor solution was 0.5 [mol / L].

  Using the precursor solution, a film is formed on the substrate on which the first drive electrode is formed by spin coating, and after the film formation, drying is performed at 120 [° C.], and then thermal decomposition is further performed at 500 [° C.]. The operation was repeated several times to laminate an electromechanical conversion film.

  When the electromechanical conversion film was laminated by repeating the above procedure, a crystallization heat treatment (temperature 750 [° C.]) was performed by RTA (rapid heat treatment) after the third thermal decomposition treatment. After the thermal decomposition treatment of the third layer, the film thickness of the electromechanical conversion film (PZT film) subjected to RTA treatment was 240 [nm].

  The above process was performed a total of 8 times (24 layers) to obtain an electromechanical conversion film having a PZT film thickness of about 2 [μm].

Next, an SrRuO ₃ film (film thickness 40 [nm]) was formed as an oxide film of the second drive electrode, and a Pt film (film thickness 125 [nm]) was formed as a metal film by sputtering.

  Thereafter, a photoresist (TSMR8800) manufactured by Tokyo Ohka Co., Ltd. was formed by spin coating, and a resist pattern was formed by ordinary photolithography. Thereafter, the electromechanical conversion film and the second drive electrode were individualized by etching using an ICP etching apparatus (manufactured by Samco), and a pattern as shown in FIG. 11 was produced. Thus, the second drive electrode functions as an individual electrode, and the first drive electrode functions as a common electrode for the individualized electromechanical conversion film and the second drive electrode.

Next, as the first insulating protective film, an Al ₂ O ₃ film having a thickness of 50 nm was formed by the ALD method.

As raw materials, trimethylaluminum (TMA) (manufactured by Sigma-Aldrich) was used as the Al source, and O ₃ generated by an ozone generator was used as the O source. Then, an Al source and an O source were alternately supplied onto the substrate and laminated to form a film.

  Thereafter, as shown in FIG. 5, a contact hole portion was formed by etching.

  Then, Al was sputtered as the first wiring and the second wiring, and was patterned by etching.

Thereafter, Si ₃ N ₄ was formed as a second insulating film to a thickness of 500 [nm] by plasma CVD. Thereafter, the common electrode pad 46, the individual electrode pad 47, and the aging treatment opening 50 were formed by etching, and an electromechanical transducer as shown in FIG. 5 was produced.

  At this time, 26 areas of 30 [mm] × 10 [mm] square in a 6-inch wafer are arranged, and among them, the pad area for individual electrodes (50 [μm] × 1000 [μm]), and the number of pads is 300 Prepared. In addition, a common electrode pad area (50 [μm] × 1000 [μm]) and 30 pads were prepared. As shown in FIG. 12, the individual electrodes 46 are respectively connected to the individual electrode connection openings 57.

  Thereafter, as shown in FIGS. 13 and 14, the substrate 31 is placed on the insulating sheet 54 on the stage 53, the conductor plate 20 is connected to the common electrode pad 46, and the individual electrode connection opening 57 is grounded. To ground. Then, electric charges were injected into the conductor plate 20 by corona charging treatment, and polarization treatment was performed.

  The corona charging treatment was performed using a tungsten wire of φ50 [μm]. The distance between the wire and the aging treatment electrode 51 as the aging treatment opening line was set to 5 [mm], a voltage of 6 [kV] was applied to the sample, and the treatment was performed for 30 minutes.

  Thereafter, as shown in FIGS. 17 and 18, the substrate 31 was made into chips by dicing, and the electromechanical transducer 30 was manufactured.

[Example 2]
In the corona charging process, an electromechanical conversion element was produced in the same manner as in Example 1 except that the voltage of the polarization process was applied instead of 8 [kV].

[Comparative Example 1]
In the corona charging process, the same procedure as in Example 1 was performed except that the corona discharge was directly performed on the common electrode pad 46 as shown in FIG. 15 without providing the aging process opening 50 and the aging process electrode 51. An electromechanical transducer was prepared.

[Comparative Example 2]
In the corona charging process, an electromechanical transducer was prepared in the same manner as in Comparative Example 1 except that the polarization voltage was applied instead of 8 [kV].

  FIG. 16 is a graph comparing the electromechanical transducers produced in Examples 1 and 2 and Comparative Examples 1 and 2, respectively. In the graph shown in FIG. 16, regarding the processing effect of the electromechanical transducer elements in the wafers produced by Examples 1 and 2 and Comparative Examples 1 and 2, respectively, the X axis is in the range of Pr-Pini, and the Y axis is in the range. Comparison is made as the ratio of the number of elements entering.

  In FIG. 16, it can be seen that failures such as cracks and discharges did not occur in Examples 1 and 2, whereas failures occurred in Comparative Examples 1 and 2. In particular, it can be seen that the failure rate is high in Comparative Example 2 where the voltage for polarization treatment is high. Further, in Comparative Example 2, there were many failures particularly in the electromechanical transducers at the end compared to the central part in the wafer.

  In addition, regarding the state of polarization processing, in Examples 1 and 2, although the polarization progressed state was different due to the difference in polarization processing voltage, processing could be performed with little processing variation. Further, in Examples 1 and 2, no failures such as cracks and discharges occurred.

FIG. 17 is an explanatory diagram for explaining a method of cutting an electromechanical transducer from a wafer, in which (a) is a top view and (b) is a cross-sectional view.
In FIG. 17B, first, the connection portion between the individual electrode pad 47 and the aging treatment electrode 51 is half-cut to the middle of the substrate 31 by a dicing blade as a cutting blade to form a half-cut line 56. The half cut line 56 may continue to the vicinity of the common electrode pad 46 as shown in FIG. Next, dicing is performed along a dicing line 55 as a cutting position outside the half-cut line 56, and the portion of the aging process electrode 51 is completely cut and cut.

  As shown in FIG. 17B, the second wiring 43 can be disconnected from each other by half-cutting the substrate 31 halfway along the half-cut line 56. Further, by half-cutting along the half-cut line 56, the end portion (fracture surface) of the second wiring 43 to which a voltage is applied during use is the outermost end portion (outermost periphery) of the electromechanical transducer 30 including the substrate 31. Can be prevented. Thereby, troubles, such as a short circuit, can be prevented beforehand.

FIG. 18 is an explanatory view for explaining another method of cutting an electromechanical transducer from a wafer, (a) is a top view, (b) is a sectional view after half-cutting, and (c) is completely cut. It is sectional drawing after having performed.
In FIG. 18B, first, the connection portion between the individual electrode pad 47 and the aging treatment electrode 51 is half-cut to the middle of the substrate 31 by a dicing blade to form a half-cut line 56. The half cut line 56 may continue to the vicinity of the common electrode pad 46 as shown in FIG. Next, as shown in FIG. 18C, by using a dicing blade that is narrower than the dicing blade used for half-cutting, dicing along the center of the half-cut line 56, the aging treatment electrode 51 is formed. Cut off the part completely.

  As shown in FIGS. 18B and 18C, by performing half-cutting in advance, the end portion (fracture surface) of the second wiring 43 to which voltage is applied in use when completely cut is the substrate. It can prevent becoming the outermost part (outermost periphery) of the electromechanical transducer 30 including 31. Thereby, troubles, such as a short circuit, can be prevented beforehand.

  Next, a configuration example of a droplet discharge apparatus including the droplet discharge head will be described. The form of the droplet discharge device is not particularly limited, but here, an ink jet recording device will be described as an example. FIG. 19 is a perspective explanatory view of the ink jet recording apparatus, and FIG. 20 is a side explanatory view of the recording apparatus.

  This ink jet recording apparatus includes a carriage 93 that can move in the main scanning direction inside the recording apparatus main body 81. Further, a recording head composed of an ink jet head mounted on the carriage 93, a printing mechanism portion 82 including an ink cartridge for supplying ink to the recording head, and the like are housed. In addition, a paper feed cassette (or a paper feed tray) 84 on which a large number of sheets 83 can be stacked from the front side can be removably attached to the lower part of the recording apparatus main body 81. The manual feed tray 85 for manually feeding the paper can be turned over. Then, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, and after a required image is recorded by the printing mechanism unit 82, the paper is discharged to a paper discharge tray 86 mounted on the rear side.

  The printing mechanism 82 holds a carriage 93 slidably in the main scanning direction by a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). The carriage 93 includes a recording head 94 including an inkjet head that ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The recording head 94 is mounted with a plurality of ink ejection openings (nozzles) arranged in a direction crossing the main scanning direction and the ink droplet ejection direction facing downward. In addition, each ink cartridge 95 for supplying ink of each color to the recording head 94 is replaceably mounted on the carriage 93.

  The ink cartridge 95 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the inkjet head below, and a porous body filled with ink inside. The ink supplied to the inkjet head is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the recording heads 94 for the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used.

  Here, the carriage 93 is slidably fitted to the main guide rod 91 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 92 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 100 is stretched between a driving pulley 98 and a driven pulley 99 that are rotationally driven by a main scanning motor 97. The timing belt 100 is fixed to the carriage 93, and the carriage 93 is driven to reciprocate by forward and reverse rotation of the main scanning motor 97.

  On the other hand, in order to convey the paper 83 set in the paper feed cassette 84 to the lower side of the recording head 94, the paper feed roller 101 and the friction pad 102 for separating and feeding the paper 83 from the paper feed cassette 84 and the paper 83 are guided. The guide member 103 is provided. Further, a conveyance roller 104 that reverses and conveys the fed paper 83, a conveyance roller 105 that is pressed against the peripheral surface of the conveyance roller 104, and a leading end roller 106 that defines a feeding angle of the sheet 83 from the conveyance roller 104; Is provided. The transport roller 104 is rotationally driven by a sub-scanning motor 107 through a gear train.

  A printing receiving member 109 is provided as a paper guide member that guides the paper 83 sent from the transport roller 104 below the recording head 94 in accordance with the movement range of the carriage 93 in the main scanning direction. On the downstream side of the printing receiving member 109 in the sheet conveyance direction, a conveyance roller 111 and a spur 112 that are rotationally driven to send out the sheet 83 in the sheet discharge direction are provided. Further, a paper discharge roller 113 and a spur 114 for sending the paper 83 to the paper discharge tray 86, and guide members 115 and 116 for forming a paper discharge path are provided.

  At the time of recording, the recording head 94 is driven according to the image signal while moving the carriage 93, thereby ejecting ink onto the stopped sheet 83 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 83 has reached the recording area, the recording operation is terminated and the paper 83 is discharged.

  Further, a recovery device 117 for recovering the ejection failure of the recording head 94 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 93. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit. The carriage 93 is moved to the recovery device 117 side during printing standby, and the recording head 94 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the recording head 94 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with a suction unit through a tube. As a result, the ink, dust, etc. adhering to the ejection port surface are removed by the cleaning means, and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since the inkjet head embodying the present invention is mounted in this inkjet recording apparatus, there is no clogging of the nozzle or solid matter adheres to the nozzle surface, so there is no ink droplet ejection failure and stable ink droplet ejection. Characteristics are obtained and image quality is improved.

[Modification 1]
In the above embodiment, the configuration in which the charge generated by the corona discharge or the glow discharge is injected from the common electrode pad 46 through the conductor plate 20 has been described. However, a dummy pad as a charge injection terminal portion may be provided. Good. An example of a manufacturing method having a configuration in which a dummy pad for charge injection is provided will be described.

  First, a thermal oxide film (film thickness: 1 [μm]) was formed on a 6-inch silicon wafer.

Next, a first drive electrode was formed. Specifically, first, as an adhesion film, a titanium film (film thickness: 30 [nm]) was formed by a sputtering apparatus, and then thermally oxidized at 750 [° C.] using RTA. Subsequently, a platinum film (film thickness 100 [nm]) was formed as a metal film, and an SrRuO ₃ film (film thickness 60 [nm]) was formed as an oxide film by sputtering. Film formation was performed at a substrate heating temperature of 550 [° C.] during the sputtering film formation.

  Next, an electromechanical conversion film was formed. Specifically, a solution having a molar ratio of Pb: Zr: Ti = 114: 53: 47 was prepared, and a film was formed by spin coating.

  For the synthesis of a specific precursor coating solution, lead acetate trihydrate, isopropoxide titanium, and normal propoxide zirconium were used as starting materials. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. The lead amount is excessive with respect to the stoichiometric composition. This is to prevent crystallinity deterioration due to so-called lead loss during heat treatment.

  Isopropoxide titanium and normal propoxide zirconium were dissolved in methoxyethanol, the alcohol exchange reaction and the esterification reaction were advanced, and the PZT precursor solution was synthesized by mixing with the methoxyethanol solution in which the lead acetate was dissolved. The PZT concentration in the synthesized PZT precursor solution was 0.5 [mol / L].

  Using the precursor solution, a film is formed on the substrate on which the first drive electrode is formed by spin coating, and after the film formation, drying is performed at 120 [° C.], and then thermal decomposition is further performed at 500 [° C.]. The operation was repeated several times to laminate an electromechanical conversion film.

  When the electromechanical conversion film was laminated by repeating the above procedure, a crystallization heat treatment (temperature 750 [° C.]) was performed by RTA (rapid heat treatment) after the third thermal decomposition treatment. After the thermal decomposition treatment of the third layer, the film thickness of the electromechanical conversion film (PZT film) subjected to RTA treatment was 240 [nm].

  The above process was performed a total of 8 times (24 layers) to obtain an electromechanical conversion film having a PZT film thickness of about 2 [μm].

Next, an SrRuO ₃ film (film thickness 40 [nm]) was formed as an oxide film of the second drive electrode, and a Pt film (film thickness 125 [nm]) was formed as a metal film by sputtering.

  Thereafter, a photoresist (TSMR8800) manufactured by Tokyo Ohka Co., Ltd. was formed by spin coating, and a resist pattern was formed by ordinary photolithography. Thereafter, the electromechanical conversion film and the second drive electrode were individualized by etching using an ICP etching apparatus (manufactured by Samco), and a pattern as shown in FIG. 11 was produced. Thus, the second drive electrode functions as an individual electrode, and the first drive electrode functions as a common electrode for the individualized electromechanical conversion film and the second drive electrode.

Next, as the first insulating protective film, an Al ₂ O ₃ film having a thickness of 50 nm was formed by the ALD method.

As raw materials, trimethylaluminum (TMA) (manufactured by Sigma-Aldrich) was used as the Al source, and O ₃ generated by an ozone generator was used as the O source. Then, an Al source and an O source were alternately supplied onto the substrate and laminated to form a film.

  Thereafter, as shown in FIG. 21, a contact hole portion was formed by etching.

  Then, Al was sputtered as the first wiring and the second wiring, and was patterned by etching.

Thereafter, Si ₃ N ₄ was formed as a second insulating film to a thickness of 500 [nm] by plasma CVD. Thereafter, the dummy pad 60 for connecting the conductive plate, the common electrode pad 46, the individual electrode pad 47, and the aging treatment opening 50 are formed by etching, and an electromechanical transducer as shown in FIG. 21 is manufactured. did.

  At this time, 26 areas of 30 [mm] × 10 [mm] square in a 6-inch wafer are arranged, and among them, the pad area for individual electrodes (50 [μm] × 1000 [μm]), and the number of pads is 300 Prepared. In addition, a common electrode pad area (50 [μm] × 1000 [μm]) and 30 pads were prepared. As shown in FIG. 12, the individual electrodes 46 are respectively connected to the individual electrode connection openings 57.

  Thereafter, as shown in FIGS. 13 and 22, the substrate 31 is disposed on the insulating sheet 54 on the stage 53, the conductor plate 20 is connected to at least one of the common electrode pad 46 and the dummy pad 60, and the individual electrodes are connected. The connection opening 57 is grounded. Then, electric charges were injected into the conductor plate 20 by corona charging treatment, and polarization treatment was performed. By disposing the substrate 31 on the insulating sheet 54 on the stage 53, leakage from the substrate 31 to the stage 53 can be prevented. Further, the electric charge injected into the conductor plate 20 is injected through at least one of the common electrode pad 46 and the dummy pad 60, and the electromechanical conversion film 34 is reliably polarized.

  The corona charging treatment was performed using a tungsten wire of φ50 [μm]. The distance between the wire and the aging electrode 51 was set to 5 [mm], a voltage of 6 [kV] was applied to the sample, and the treatment was performed for 30 minutes.

  Thereafter, as shown in FIGS. 17 and 18, the substrate 31 was made into chips by dicing, and the electromechanical transducer 30 was manufactured.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A method of manufacturing the electromechanical transducer 30, wherein the step of forming the first drive electrode 33 on the substrate 31 or the base film formed on the substrate 31 and the first drive electrode 33 are independent of each other. Forming a plurality of electromechanical conversion films 34 and a plurality of second drive electrodes 35 positioned on each of the plurality of electromechanical conversion films 34; and on the first drive electrodes 33 and the plurality of second drives. A step of forming a first insulating protective film 41 on the electrode 35, and a first terminal electrode such as a common electrode pad 46 electrically connected to the first drive electrode 33 via a first wiring 42. A plurality of second terminal electrodes such as individual electrode pads 47 electrically connected to each of the plurality of second drive electrodes 35 via the second wiring 43, and a plurality of second terminal electrodes. Electrically connected aging electrode 1 is formed on the first insulating protective film 41, and is a film formed on the first wiring 42 and the second wiring 43. The first terminal electrode and the second electrode A step of forming a second insulating protective film 44 exposing the terminal electrode of the conductive member, and a conductive member such as a conductor plate 20 having a contact portion 20b corresponding to the first terminal electrode. 20b is brought into electrical contact with the first terminal electrode, and the electric charge generated by the discharge is injected into the first drive electrode 33 through the conductive member. And polarization processing.
According to this, as described in the above embodiment, when the electromechanical conversion film 34 is subjected to the polarization process, the contact portion 20b of the conductive member is exposed in the second insulating protective film 44. Charges generated by discharge are injected into the conductive member in contact with the terminal electrode. The electric charge generated and injected by this discharge is injected into the first drive electrode 33 through the conductive member, the first terminal electrode, and the first wiring 42. Thus, the electric charge generated by the discharge is surely injected into the first drive electrode 33, and the electromechanical conversion film 34 can be collectively polarized. Further, since the polarization process is performed after the formation of the second insulating protective film 44 to which high-temperature heat is applied, the polarized electromechanical conversion film 34 is not heated, and therefore the electromechanical conversion film 34 is removed after the polarization process. Polarization can be prevented. In addition, during the polarization process, the plurality of second drive electrodes formed for each of the plurality of electromechanical conversion films 34 are electrically connected to the collective electrodes of a predetermined potential, and the plurality of second drive electrodes are electrically connected. The potential of the drive electrode 35 is kept at a predetermined magnitude. Therefore, a uniform polarization process can be performed without concentration of charges on some electromechanical conversion films 34. As described above, it is possible to reduce the variation in the polarization characteristics of the electromechanical transducer while preventing the occurrence of depolarization after the polarization process while improving the manufacturing efficiency.
(Aspect B)
In the aspect A, the first terminal electrode has an external connection terminal portion such as the common electrode pad 46 and a charge injection terminal portion such as the dummy pad 60 that contacts the contact portion 20b of the conductive member. In the step of polarizing the electromechanical conversion film 34, the contact portion 20b of the conductive member is brought into electrical contact with the charge injection terminal portion of the first terminal electrode, and is generated by discharge through the conductive member. The plurality of electromechanical conversion films 34 are collectively polarized by injecting the charged charges into the first drive electrode.
According to this, as described in the first modification, charges are injected into the charge injection terminal portion different from the external connection terminal portion such as the common electrode pad 46 in the first terminal electrode. Therefore, it is possible to suppress damage to the external connection terminal portion to which a voltage is applied during actual use.
(Aspect C)
In the aspect A or aspect B, in the step of forming the second insulating protective film 44, the second insulating protective film 44 is formed by exposing the collective electrode, and the collective electrode is grounded.
According to this, as described in the above embodiment, the collective electrode exposed from the second insulating protective film 44 can be easily grounded to the ground. In addition, the potentials of the plurality of second drive electrodes 35 electrically connected to the collective electrode are stably maintained at the ground potential. Therefore, it is possible to more reliably prevent charge concentration on a part of the electromechanical conversion film 34 and perform more uniform polarization processing.
(Aspect D)
In any of the above aspects A to C, the material of the conductive member is the same as the material of the first terminal electrode with which the contact portion 20b contacts.
According to this, as described in the above embodiment, the contact resistance between the contact portion 20b of the conductive member and the first terminal electrode can be reduced, and the charge injection efficiency via the first terminal electrode can be reduced. Can be increased.
(Aspect E)
In any of the above-described aspects A to D, a step of forming the first insulating protective film 41 and a step of forming the second insulating protective film 44, each including a plurality of the first drive electrodes and the first terminal electrodes. in, exposing the plurality of first terminal electrodes forming each insulating protective film, the conductive member has a plurality of first terminal electrodes and the same number of contact contact portion 20b.
According to this, as described in the above embodiment, when a plurality of the first drive electrodes and a plurality of first terminal electrodes are provided, a plurality of electricity corresponding to each of the plurality of first drive electrodes is provided. The mechanical conversion film 34 can be polarized at once. Therefore, manufacturing efficiency can be further improved.
(Aspect F)
In the above embodiment E, the first terminal electrode has a charge injection terminal portion such as the dummy pad 60 contacting the contact portion 20b of the conductive member, a first terminal electrode contacting contact portion 20b of the conductive member Or the area of the part which contacts the terminal part for electric charge injection is below the area of the 1st terminal electrode or the terminal part for electric charge injection.
According to this, as described in the above-described embodiment, the contact portion 20b of the conductive member reliably contacts the first terminal electrode or the charge injection terminal portion, and the charge injection efficiency via the conductive member. Can be maintained.
(Aspect G)
In any one of the above aspects A to F, the area of the surface into which charges generated by the discharge of the conductive member are injected is equal to or larger than the area of the substrate.
As described in the above embodiment, when the area of the surface into which the charge generated by the discharge of the conductive member is injected is smaller than the area of the substrate 31, the charge generated by the discharge is other than the first drive electrode 33. It will be injected into the electrode. Then, the desired effect in the polarization treatment may not be obtained. According to this aspect G, since the area of the surface into which charges generated by the discharge of the conductive member are injected is equal to or larger than the area of the substrate 31, the charge injection to the electrodes other than the first drive electrode 33 is suppressed. And a desired effect in the polarization treatment can be obtained.
(Aspect H)
In any one of the above aspects A to G, the method includes a step of cutting the plurality of electromechanical conversion elements 30 formed on the substrate 31 or the base film so as to be separated from each other and to be individualized, and the plurality of second terminals In the step of forming the collective electrode electrically connected to the electrode on the first insulating protective film 41 , the collective electrode is formed at a position away from the second terminal electrode with respect to the electromechanical conversion film 34, In the step of individualizing the electromechanical transducer 30, the plurality of second terminal electrodes and the collective electrode are cut.
According to this, as described in the above embodiment, by cutting between the plurality of second terminal electrodes and the collecting electrode, the conduction between the plurality of second terminal electrodes and the collecting electrode is cut, A driving voltage can be applied to each second terminal electrode independently of each other. Therefore, the individual drive of each electromechanical transducer 30 can be reliably performed.
(Aspect I)
In the above aspect H, the step of individualizing the electromechanical conversion element 30 is such that the second terminal electrode side in the thickness direction of the substrate 31 is located at the cutting position where the second terminal electrode and the collecting electrode are completely cut. Including a step of cutting halfway.
According to this, as described in the above embodiment, the end portion (fracture surface) of the second wiring 43 to which a voltage is applied during use is at the outermost end portion (outermost periphery) of the electromechanical transducer 30 including the substrate 31. It is possible to prevent troubles such as a short circuit.
(Aspect J)
In the aspect H, the step of individualizing the electromechanical transducer 30 includes a step of cutting between the second terminal electrode and the collecting electrode halfway in the thickness direction of the substrate 31 with a cutting blade, and a width wider than the cutting blade. A step of completely cutting the substrate 31 with a narrow cutting blade at a position where the substrate 31 is cut halfway in the thickness direction.
According to this, as described in the above embodiment, the portion to be cut can be cut in advance to the middle of the substrate 31. Thus, when the electromechanical conversion element 30 is completely cut and the electromechanical conversion element 30 is separated, the end (fracture surface) of the second wiring 43 to which a voltage is applied during use is the endmost part of the electromechanical conversion element 30 including the substrate 31 (Outermost circumference) can be prevented and troubles such as a short circuit can be prevented.
(Aspect K)
In any of the above aspects A to J, in the step of performing the polarization treatment, the charge generated by the discharge is negatively charged.
According to this, as described in the above embodiment, anions having a charge charged to negative polarity can be easily generated by ionizing molecules in the atmosphere by discharge. The negative ions flow into the electromechanical conversion element 30 through the first terminal electrode connected to the first wiring 42, so that the negatively charged charge can be easily accumulated in the electromechanical conversion element 30. it can. Therefore, the polarization process of the electromechanical conversion film 34 can be performed stably.
(Aspect L)
In any of the above aspects A to K, in the step of performing the polarization treatment, a charge amount of 1.0 × 10 ⁻⁸ [C] or more is generated by discharge.
According to this, as described in the above embodiment, when the charge amount due to the discharge is less than 1.0 × 10 ⁻⁸ [C], the polarization process cannot be sufficiently performed, and the electromechanical conversion film 34 is not formed. When used in an actuator, there is a possibility that sufficient characteristics cannot be obtained with respect to displacement deterioration after continuous driving. In the present aspect L, since the charge amount due to the discharge is 1.0 × 10 ⁻⁸ [C] or more, the polarization process can be sufficiently performed, and the electromechanical conversion film 34 is used as an actuator. In addition, sufficient characteristics can be obtained with respect to displacement deterioration after continuous driving.
(Aspect M)
A polarization processing apparatus for an electromechanical transducer for implementing any one of the above aspects A to L, for generating a discharge of a corona wire 52 or the like, or for controlling a discharge electrode and a discharge A grid electrode, a stage 53 for installing the substrate 31, and a conductive member are provided, the stage 53 is grounded to the ground, and the stage 53 and the substrate 31 are insulated by an insulator. It has at least one of the configurations.
According to this, as described in the above embodiment, the electromechanical transducer 30 can be efficiently manufactured on the substrate 31 placed on the stage 53. Furthermore, since the stage 53 is grounded to the ground, the potential of the electromechanical conversion film 34 is stabilized, and a more uniform polarization process can be performed without charge concentration on a part of the electromechanical conversion film 34. . Further, by insulating the substrate 31 and the stage 53 with an insulator, it is possible to prevent the charge injected into the substrate 31 from leaking from the stage 53.
(Aspect N)
The electromechanical transducer 30 obtained by the method of manufacturing an electromechanical transducer according to any one of the above aspects A to L, wherein the polarization of the electromechanical transducer is a hysteresis with an electric field strength of ± 150 [kV / cm] When measuring the loop, the polarization at 0 [kV / cm] at the start of measurement is Pini, and after applying a voltage of +150 [kV / cm], 0 [kV / cm] when returning to 0 [kV / cm] When the time polarization is Pr, the difference between Pr and Pini is 10 [μC / cm ² ] or less.
According to this, as described in the above embodiment, it is possible to reduce the variation in the polarization characteristics of the electromechanical transducer 30 while preventing the occurrence of depolarization after the polarization process while improving the manufacturing efficiency. An electromechanical transducer that can be provided can be provided. In addition, it is possible to provide an electromechanical conversion element capable of reliably performing a uniform polarization process on a plurality of electromechanical conversion films in a short time and improving the yield. When the difference between Pr and Pini is larger than 10 [μC / cm ² ], there is a possibility that sufficient characteristics cannot be obtained with respect to displacement deterioration after continuous driving when the electromechanical conversion film 34 is used as an actuator. In the aspect O, since the difference between Pr and Pini is 10 [μC / cm ² ] or less, when the electromechanical conversion film 34 is used as an actuator, sufficient characteristics can be obtained with respect to displacement deterioration after continuous driving.
(Aspect O)
In the above aspect N, the relative permittivity of the electromechanical conversion film 34 is 600 or more and 2000 or less.
As described in the above embodiment, if the relative dielectric constant is smaller than 600, there is a possibility that sufficient displacement characteristics cannot be obtained when the electromechanical conversion film 34 is used for an actuator. Further, if the relative dielectric constant is larger than 2000, the polarization process is not sufficiently performed, and there may be a problem that a sufficient characteristic cannot be obtained for the displacement deterioration after continuous driving. In the aspect F, since the relative dielectric constant of the electromechanical conversion film 34 is 600 or more and 2000 or less, sufficient displacement characteristics can be obtained when the electromechanical conversion film 34 is used for an actuator. Further, the polarization process is sufficiently performed, and sufficient characteristics can be obtained with respect to displacement deterioration after continuous driving.
(Aspect P)
In the above aspect N or O, the first wiring 42 electrically connected to the first drive electrode 33 and the second wiring 43 electrically connected to the second drive electrode 35 are in the same process. Made in.
According to this, as described in the above embodiment, the number of processing steps and the processing time can be reduced and the cost can be reduced as compared with the case of being manufactured by separate processes.
(Aspect Q)
In any one of the above aspects N to P, at least one of the first wiring 42 and the second wiring 43 is a metal electrode material made of any one of Ag alloy, Cu, Al, Al alloy, Au, Pt, and Ir. Is formed.
According to this, as described in the above embodiment, these metals can form a low-resistance and durable electrode on the substrate.
(Aspect R)
In any one of the above aspects N to Q, at least one of the first insulating protective film 41 and the second insulating protective film 44 is an inorganic material selected from an alumina film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film. It is a membrane.
According to this, as described in the above embodiment, these films have good adhesion, hard films, and excellent wear resistance and cost performance. An insulating protective film 44 can be formed.
(Aspect S)
In the droplet discharge head 10 including a nozzle 11 that discharges a droplet, a pressure chamber 12 that communicates with the nozzle 11, and a discharge drive unit that pressurizes the liquid in the pressure chamber 12, the discharge drive unit 10 A part of the wall of the pressure chamber 12 is constituted by the diaphragm 17, and the electromechanical transducer element according to any one of the above embodiments O to R is arranged on the diaphragm 17.
According to this, as described in the above embodiment, the liquid in the pressurizing chamber 12 can be boosted by the electromechanical conversion element that has been reliably subjected to the polarization process without depolarization. Discharge characteristics can be obtained.
(Aspect T)
A droplet discharge apparatus including the droplet discharge head according to aspect S. According to this, as described in the above embodiment, stable droplet discharge characteristics can be obtained.

DESCRIPTION OF SYMBOLS 10 Droplet discharge head 11 Nozzle 12 Pressurization chamber 13 Electromechanical conversion film 14 Upper electrode 15 Lower electrode 16 Electromechanical conversion element 17 Base film (vibration plate)
20 Conductor plate 20a Plate part 20b Contact part 30 Electromechanical transducer 31 Substrate 32 Film-forming diaphragm (underlayer)
33 First drive electrode 34 Electromechanical conversion film 35 Second drive electrode 41 First insulating protective film 42 First wiring 43 Second wiring 44 Second insulating protective film 45 Contact hole 46 Common electrode pad 47 Individual Electrode Pad 50 Aging Process Opening 51 Aging Process Electrode 52 Corona Wire 53 Stage 55 Dicing Line 56 Half Cut Line 60 Dummy Pad 81 (Inkjet) Recording Device Main Body 82 Printing Mechanism Unit 93 Carriage 94 Recording Head 95 Ink Cartridge 117 Recovery device

JP 2004-202849 A JP 2010-034154 A JP 2006-203190 A Japanese Patent No. 3784401

Claims (19)

A method of manufacturing an electromechanical transducer that forms a plurality of electromechanical transducers,
Forming a first drive electrode on a substrate or a base film formed on the substrate;
Forming a plurality of electromechanical conversion films independent of each other on the first drive electrode, and a plurality of second drive electrodes positioned on each of the plurality of electromechanical conversion films;
Forming a first insulating protective film on the first drive electrode and the plurality of second drive electrodes;
A first terminal electrode electrically connected to the first drive electrode via a first wiring; and a first terminal electrode electrically connected to each of the plurality of second drive electrodes via a second wiring. Forming a plurality of second terminal electrodes and a collecting electrode electrically connected to the plurality of second terminal electrodes on the first insulating protective film;
Forming a second insulating protective film which is a film formed on the first wiring and the second wiring and which exposes the first terminal electrode, the second terminal electrode and the collecting electrode; Steps,
A conductive member having a contact portion corresponding to the first terminal electrode is used, and the contact portion of the conductive member is brought into electrical contact with the first terminal electrode and discharged via the conductive member. by injecting electric charges generated in the first driving electrode by, have a, a step of polarization process collectively the plurality of electromechanical conversion film,
In the step of forming the second insulating protective film, the collecting electrode is exposed to form the second insulating protective film,
The method of manufacturing an electromechanical transducer element, wherein the collective electrode is grounded . In the manufacturing method of the electromechanical transducer of claim 1,
The first terminal electrode has an external connection terminal part and a charge injection terminal part for contacting the contact part of the conductive member,
In the step of polarizing the electromechanical conversion film, the contact portion of the conductive member is brought into electrical contact with the charge injection terminal portion of the first terminal electrode, and is discharged through the conductive member. A method of manufacturing an electromechanical conversion element, wherein the plurality of electromechanical conversion films are collectively polarized by injecting the generated charges into the first drive electrode. In the manufacturing method of the electromechanical transducer of Claim 1 or 2 ,
The method of manufacturing an electromechanical transducer element, wherein the material of the conductive member is the same as the material of the first terminal electrode with which the contact portion contacts. In the method for manufacturing an electromechanical transducer according to any one of claims 1 to 3 ,
A plurality of the first drive electrodes and the first terminal electrodes, respectively,
In the step of forming the first insulating protective film and the step of forming the second insulating protective film, the plurality of first terminal electrodes are exposed to form each insulating protective film,
Said conductive member, the manufacturing method of electromechanical transducer which comprises said contact contact portion in the same number as that of said plurality of first terminal electrodes. In the manufacturing method of the electromechanical transducer of Claim 4 ,
The first terminal electrode has a charge injection terminal portion and the contact portion you contact of the conductive member,
Area of the portion in contact with said first terminal electrodes or the charge injection terminal portions of the contact contact portion of the conductive member is less area of the terminal electrode or charge injection terminal portion of the first A method for manufacturing an electromechanical conversion element. In the method of manufacturing an electromechanical transducer according to any one of claims 1 to 5 ,
The method of manufacturing an electromechanical conversion element, wherein an area of a surface into which charges generated by the discharge of the conductive member are injected is equal to or larger than an area of the substrate. In the method for manufacturing an electromechanical transducer according to any one of claims 1 to 6 ,
Cutting the plurality of electromechanical conversion elements formed on the substrate or the base film so as to be separated from each other and individualized,
In the step of forming a collective electrode electrically connected to the plurality of second terminal electrodes on the first insulating protective film, the collective electrode is connected to the electromechanical conversion film by the second terminal electrode. Formed at a position farther away,
In the step of individualizing the electromechanical transducer, the method for producing an electromechanical transducer is characterized by cutting between the plurality of second terminal electrodes and the collective electrode. In the manufacturing method of the electromechanical transducer of claim 7 ,
The step of individualizing the electromechanical conversion element is such that the second terminal electrode side is partway in the thickness direction of the substrate from the cutting position at which the space between the second terminal electrode and the collecting electrode is completely cut. A method for manufacturing an electromechanical transducer, comprising a step of cutting. In the manufacturing method of the electromechanical transducer of claim 7 ,
The step of individualizing the electromechanical transducer element comprises:
Cutting between the second terminal electrode and the collective electrode to the middle of the thickness direction of the substrate with a cutting blade;
And a step of completely cutting around the position where the substrate is cut halfway in the thickness direction with a cutting blade having a width narrower than that of the cutting blade. In the method for manufacturing an electromechanical transducer according to any one of claims 1 to 9 ,
The method for manufacturing an electromechanical transducer, wherein in the step of performing the polarization treatment, the electric charge generated by the discharge is charged negatively. The manufacturing method of any of the electromechanical transducer of claims 1 to 1 0,
In the step of performing the polarization treatment, a charge amount of 1.0 × 10 ⁻⁸ [C] or more is generated by the discharge. An electromechanical transducer polarization treatment apparatus for carrying out the method of manufacturing an electromechanical transducer according to any one of claims 1 to 11,
A discharge electrode for generating the discharge, or a grid electrode for controlling the discharge electrode and discharge;
A stage for installing the substrate;
The conductive member,
A polarization processing apparatus for an electromechanical transducer having at least one of a configuration in which the stage is grounded to ground and a configuration in which the stage and the substrate are insulated by an insulator. An electromechanical transducer obtained by the method for producing an electromechanical transducer according to any one of claims 1 to 11,
When measuring the hysteresis loop by applying an electric field strength of ± 150 [kV / cm] as the polarization of the electromechanical conversion film, the polarization at 0 [kV / cm] at the start of the measurement is Pini, and +150 [kV / cm ], When the polarization at 0 [kV / cm] when returning to 0 [kV / cm] is Pr, the difference between Pr and Pini is 10 [μC / cm ² ] or less. An electromechanical conversion element characterized by that. In electromechanical transducer according to claim 1 3,
The electromechanical transducer having a relative dielectric constant of 600 or more and 2000 or less. In electromechanical transducer according to claim 1 3 or 1 4,
The first wiring electrically connected to the first driving electrode and the second wiring electrically connected to the second driving electrode are formed in the same process. A characteristic electromechanical transducer. In any of the electromechanical transducer according to claim 1 3 to 1 5,
At least one of the first wiring and the second wiring is formed of a metal electrode material made of any one of Ag alloy, Cu, Al, Al alloy, Au, Pt, and Ir. Mechanical conversion element. In any of the electromechanical transducer according to claim 1 3 to 1 6,
At least one of the first insulating protective film and the second insulating protective film is an inorganic film of any one of an alumina film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film. Conversion element. In a droplet discharge head comprising a nozzle that discharges a droplet, a pressure chamber that communicates with the nozzle, and a discharge driving means that pressurizes the liquid in the pressure chamber.
Liquid as the discharge driving means, a portion of the wall of the pressurizing chamber formed of a diaphragm, characterized in that a one of the electromechanical transducer according to claim 1 3 to 1 7 to the diaphragm Drop ejection head. A droplet discharge apparatus comprising the droplet discharge head according to claim 18 .