JP5736829B2 - Method for producing electromechanical transducer, electromechanical transducer produced by this production method, ink jet head and ink jet recording apparatus using the same - Google Patents

Description

  The present invention relates to a method for manufacturing an electromechanical conversion element suitable for the case where an orientation control layer of an electromechanical conversion film is provided, an electromechanical conversion element manufactured by this manufacturing method, an ink jet head using the same, and an ink jet recording apparatus. .

  2. Description of the Related Art Conventional inkjet recording apparatuses have many advantages such as extremely low noise, high-speed printing, and the ability to use inexpensive plain paper with a high degree of ink freedom. For this reason, inkjet recording apparatuses are widely used as image recording apparatuses such as printers, copiers, and facsimile machines.

  In this type of ink jet recording apparatus, an ink jet head is used. The ink jet head includes a nozzle unit that ejects ink droplets, a pressurizing chamber unit to which the nozzle unit is connected, and a pressure generating unit that pressurizes ink in the pressurizing chamber unit.

  The pressure generating unit is provided with pressure generating means. The pressure generating means opposes an electromechanical conversion element such as a piezoelectric element that pressurizes ink in the pressurizing chamber, an electrothermal conversion element such as a heater, or a diaphragm that forms the wall of the pressurizing chamber. A thing provided with the energy generation means which consists of electrodes is used.

  Among these pressure generating means, the piezo-type ink jet head using electromechanical transducers is superior to other types of ink jet heads in terms of speed, density, and droplet viscosity. Because of this, development is actively underway.

  This electromechanical conversion element is configured by laminating a lower electrode (first electrode), an electromechanical conversion film, and an upper electrode (second electrode). By energizing the lower electrode and the upper electrode, the electromechanical conversion film is deformed to press the diaphragm of the pressurizing chamber, and the ink in the pressurizing chamber is ejected from the nozzle portion.

  The ink jet head has a plurality of pressurizing chambers. In order to generate ink discharge pressure in each of the pressurizing chambers, an individual electromechanical conversion element is arranged for each pressurizing chamber.

  As the electromechanical conversion film, lead zirconate titanate (PZT) ceramics or the like is used. Since this is mainly composed of a plurality of metal oxides, it is generally called a metal composite oxide.

  On the other hand, it is known that the displacement characteristics of this type of electromechanical transducer vary greatly depending on the crystal orientation of the electromechanical transducer film. That is, by improving the crystallinity of the electromechanical conversion film, the amount of displacement of the electromechanical conversion element can be increased, and the durability can be improved by suppressing breakage of the electromechanical conversion film. For this reason, an electromechanical conversion element has been proposed in which the crystals of the electromechanical conversion film have a predetermined orientation.

  For example, an electromechanical conversion element in which a lower electrode, an orientation control layer, an electromechanical conversion film, and an upper electrode are stacked on a silicon substrate has been developed (see, for example, Patent Document 1).

In this electromechanical transducer, the orientation control layer is formed by depositing lanthanum nickelate (LaNi _y O _x ) on the upper surface side of the lower electrode by sputtering. Such an orientation control layer made of lanthanum nickelate is substantially unaffected by the plane orientation of the lower electrode, is made of a crystal having a perovskite structure, and the crystal plane orientation is preferentially oriented to (111). . The thickness of the orientation control layer is 2 nm to 50 nm.

  An electromechanical conversion film made of PZT is formed on the upper surface side of the orientation control layer. The electromechanical conversion film is epitaxially grown under the influence of the crystal orientation of the orientation control layer, so that the crystal plane orientation is oriented to (111).

  Here, as a method for manufacturing the orientation control layer, a vacuum film forming method such as a sputtering method is employed. In the vacuum film forming method, it is impossible to form a film only on a necessary portion, and therefore, the film is formed on the entire upper surface side of the lower electrode. Then, a necessary portion is removed from the film formed on the entire surface by photolithography and etching to obtain a desired film formation pattern.

  However, in the electromechanical conversion element described above, since the vacuum film formation method is adopted as the method for manufacturing the orientation control layer, the film is formed on the entire surface of the lower electrode, and photolithography and etching processes are necessary after the film formation. Thus, there is a problem that the work becomes complicated. In addition, since the material of the part to be removed is wasted, it has been desired to reduce the cost by reducing the waste.

  As a film forming method other than the vacuum film forming method, for example, a spin film forming method which is one of sol-gel methods is known. However, even with the spin film formation method, since the film is formed on the entire surface of the lower electrode, the same problem as the vacuum film formation method described above occurs. In addition, in the spin film formation method, the lower limit value of the film thickness that can be formed is 30 nm, and if an orientation control layer having a thinner film thickness is to be formed, the film quality may become non-uniform. For this reason, an orientation control layer having a desired thickness may not be formed.

  The present invention has been made in view of the above problems, and when forming an orientation control layer, it is possible to form a film by patterning only a necessary portion without forming the entire surface, and to reduce the thickness of the orientation control layer. An object of the present invention is to provide a method for producing an electromechanical conversion element, an electromechanical conversion element produced by the production method, an ink jet head using the electromechanical conversion element, and an ink jet recording apparatus.

Method for manufacturing electromechanical transducer according to the present invention, for this purpose achieve, on a substrate, formed by laminating a first electrode, an orientation control layer, and the electro-mechanical conversion film, and a second electrode In the method of manufacturing an electromechanical conversion element for manufacturing an electromechanical conversion element, a first electrode forming step of forming the first electrode made of a platinum group alloy on the surface side of the substrate, and a surface of the first electrode An alignment control layer forming step for forming the alignment control layer on the side, an electromechanical conversion film forming step for forming the electromechanical conversion film on the surface side of the alignment control layer, and a surface side of the electromechanical conversion film in, e Bei a second electrode forming step of forming the second electrode, the orientation control layer forming step, first of applying the first alignment control layer precursor solution on the surface side of the electrode In the second part other than the part, adhesion of the alignment control layer precursor solution is prevented. A surface modification step of subjecting the surface modification of the nozzle of the liquid discharge head is opposed to the first portion of the surface side of the first electrode surface modification is performed by the surface modification step, By discharging the alignment control layer precursor solution made of sol from the nozzle, the alignment control layer precursor is applied to the first portion of the first electrode that has not been surface-modified by the surface modification step. a coating step of coating a body solution, and crystallized from the coating step by the first of the orientation control layer was coated on the first portion of the electrode precursor solution to heat treatment to the first on the electrode the A heat treatment step for forming an orientation control layer, and the surface modification of the first electrode on which the orientation control layer is formed of an oxide, the surface modification is performed, whereby the first orientation control layer is formed. Surface modification to the second part other than the part In the first portion where the orientation control layer is formed on the surface side of the first electrode subjected to the surface modification by the second surface modification step and the second surface modification step. A second application step of applying the PZT precursor solution to the surface of the orientation control layer by causing the nozzle of the liquid discharge head to face each other and discharging a PZT precursor solution made of sol from the nozzle; it is characterized in that chromatic and second heat treatment step of forming the electro-mechanical conversion film by crystallization annealing the PZT precursor solution applied by the second applying step.

  Accordingly, since the alignment control layer is formed by the sol-gel method using a liquid discharge head (that is, an inkjet head) in the alignment control layer forming step, the entire surface is formed when the alignment control layer is formed on the first electrode. Without forming a film, it is possible to form a film by selectively patterning only necessary portions.

  For this reason, the film is not formed on the entire surface of the first electrode unlike the conventional case where the vacuum film formation method or the spin film formation method is adopted as the method of manufacturing the orientation control layer. Photolithography and etching steps are not necessary. Therefore, the alignment control layer can be easily formed, and the application of the alignment control layer precursor solution to unnecessary portions that have been finally removed in the past can be eliminated, thereby contributing to cost reduction. .

  In addition, since the alignment control layer is formed by a sol-gel method using a liquid discharge head, the alignment control layer can be made thinner than in the case of forming a film by vacuum film formation or spin film formation as in the past. Can be planned. As a result, the degree of orientation of the orientation control layer is increased (see FIG. 10), so that the displacement characteristics of the electromechanical conversion film can be improved.

  Here, for example, when the first electrode is a noble metal element, the surface side of the first electrode exhibits wettability, and therefore there is a possibility that the alignment control layer precursor solution spreads in a concentric manner. On the other hand, according to the method for manufacturing an electromechanical transducer according to the present invention, the alignment control layer precursor solution adheres to a portion other than the portion to which the alignment control layer precursor solution on the surface side of the first electrode is applied. It becomes difficult. Thereby, the orientation control layer having a desired pattern can be formed with high accuracy.

  In the method for manufacturing an electromechanical conversion element according to the present invention, the orientation control layer precursor solution is preferably a lead titanate precursor solution containing at least lead and titanium.

  Thereby, since the lead titanate layer can be formed as the orientation control layer, the degree of orientation of the orientation control layer can be increased and the displacement characteristics of the electromechanical conversion film can be improved.

  In the method for manufacturing an electromechanical transducer according to the present invention, the lead titanate precursor solution preferably contains at least lead acetate and a titanium salt.

  Thereby, since the lead titanate layer can be formed as the orientation control layer, the degree of orientation of the orientation control layer can be increased and the displacement characteristics of the electromechanical conversion film can be improved. Examples of the titanium salt here include alkoxide, chloride, nitrate, acetate, and the like.

  In the method for manufacturing an electromechanical transducer according to the present invention, the film thickness of the orientation control layer is preferably 2 nm to 50 nm.

  Thereby, since the orientation control layer is sufficiently thin, the degree of orientation of the orientation control layer can be increased and the displacement characteristics of the electromechanical conversion film can be improved.

  In the method for manufacturing an electromechanical transducer according to the present invention, the preferred orientation of the electromechanical transducer film by the orientation control layer is preferably (111).

  Thereby, since the crystal plane orientation of the electromechanical conversion film formed on the orientation control layer is oriented to (111), the displacement characteristics of the electromechanical conversion film can be improved.

  In the method for manufacturing an electromechanical conversion element according to the present invention, the electromechanical conversion film preferably includes at least one of lead, zirconium, and titanium.

  Thereby, since the displacement characteristic of the electromechanical conversion film is improved, the displacement amount of the electromechanical conversion element is increased, and the durability of the electromechanical conversion film is increased.

  The electromechanical transducer according to the present invention is manufactured by the above-described method for manufacturing an electromechanical transducer. Thereby, an electromechanical transducer having a large displacement can be obtained at a low cost.

  An ink jet head according to the present invention includes the above-described electromechanical conversion element. Thereby, a high-performance inkjet head can be obtained at low cost by using an inexpensive electromechanical transducer having a large displacement.

  An ink jet recording apparatus according to the present invention includes the liquid discharge head described above. Accordingly, a high-performance ink jet recording apparatus can be obtained by using an inexpensive electromechanical transducer having a large displacement.

  According to the present invention, since the alignment control layer is formed by a sol-gel method using a liquid discharge head, it is possible to form a film by patterning only a necessary portion without forming the entire surface when forming the alignment control layer. In addition, it is possible to provide an electromechanical conversion element manufacturing method capable of making the orientation control layer thin, an electromechanical conversion element manufactured by the manufacturing method, an ink jet head using the same, and an ink jet recording apparatus.

It is a schematic longitudinal cross-sectional view which shows the inkjet head carrying the electromechanical conversion element which concerns on embodiment of this invention. 1 is a partially exploded perspective view showing a state in which a part of an inkjet head equipped with an electromechanical transducer according to an embodiment of the present invention is cut. It is the schematic which shows the orientation control layer formation process in the manufacturing method of the electromechanical conversion element which concerns on embodiment of this invention, (a) is the state which formed the SAM film in the platinum group electrode, (b) is a photoresist. (C) is a state where a pattern is formed, (c) is a state where all the photoresist is removed after removing a portion of the SAM film where no photoresist is present, and (d) is a case where the alignment control layer precursor solution is applied to a portion where the SAM film is not present State (e) shows a state in which the alignment control layer is formed by applying a heat treatment to the alignment control layer precursor solution and all the SAM films are removed. It is the schematic which shows the electromechanical conversion film formation process in the manufacturing method of the electromechanical conversion element which concerns on embodiment of this invention, (a) is the state which formed the SAM film in the part without an orientation control layer, (b) Shows a state in which the PZT precursor solution is applied to the orientation control layer, and (c) shows a state in which the PZT precursor solution is subjected to heat treatment to form an electromechanical conversion film and all SAM films are removed. 1 is a schematic perspective view showing a liquid discharge coating apparatus equipped with a liquid discharge head for manufacturing an electromechanical conversion element by an electromechanical conversion element manufacturing method according to an embodiment of the present invention. 1 is a schematic perspective view showing an ink jet recording apparatus equipped with an ink jet head according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing an inkjet recording apparatus equipped with an inkjet head according to an embodiment of the present invention. It is a graph which shows an example of the PE hysteresis curve of the electromechanical conversion film | membrane in the electromechanical conversion element which concerns on Example 8 of this invention. It is a graph which shows the relationship between the angle and the intensity | strength by the XRD analysis of the electromechanical conversion film in the electromechanical conversion element which concerns on Example 8 of this invention. It is a graph which shows the relationship between the film thickness of the orientation control layer by the XRD analysis of the electromechanical conversion film in the electromechanical conversion element which concerns on Example 10 of this invention, and orientation degree. It is a graph which shows an example of the PE hysteresis curve of the electromechanical conversion film | membrane in the electromechanical conversion element which concerns on Example 10 of this invention. It is a photograph which shows the mode of the contact angle of the pure water in the surface with the SAM film | membrane arrange | positioned in the manufacturing method of the electromechanical conversion element which concerns on Example 1 of this invention. It is a photograph which shows the mode of the contact angle of the pure water in the electrode exposure surface which removed the SAM film | membrane in the manufacturing method of the electromechanical conversion element which concerns on Example 1 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. First, with reference to FIG. 1 and FIG. 2, the inkjet head provided with the electromechanical conversion element manufactured by the manufacturing method of the electromechanical conversion element which concerns on embodiment of this invention is demonstrated.

  The inkjet head 1 according to this embodiment includes a nozzle plate 10, a silicon substrate 20, a vibration plate 30, and an electromechanical conversion element 40 that are stacked. That is, the inkjet head 1 is of a side shooter type that discharges ink droplets from the nozzle holes 11 of the nozzle plate 10.

  The silicon substrate 20 includes a plurality of pressurizing chambers 21 formed so as to penetrate in the thickness direction, a common liquid chamber 22, and fluid resistance passages 23 respectively connecting the pressurizing chambers 21 and the common liquid chamber 22. I have. As a result, the ink that has flowed into the common liquid chamber 22 flows through each fluid resistance passage 23 and is supplied to each pressure chamber 21. Each pressurizing chamber 21, each fluid resistance passage 23, and the common liquid chamber 22 are partitioned by a partition wall 24.

  The nozzle plate 10 includes a nozzle hole 11 for each pressurizing chamber 21. The vibration plate 30 includes an ink supply port 31 formed by opening a portion facing the common liquid chamber 22. The ink supply port 31 can supply ink discharged as droplets to the common liquid chamber 22 from the outside.

  The electromechanical transducer 40 includes a lower electrode 41 as a first electrode, an orientation control layer 42, an electromechanical transducer film 43, and an upper electrode 44 as a second electrode. The lower electrode 41 includes a stacked oxide electrode 45 and a platinum group electrode 46.

  The lower electrode 41 is formed throughout the diaphragm 30. The orientation control layer 42, the electromechanical conversion film 43, and the upper electrode 44 are separately provided at positions corresponding to the pressurizing chambers 21. As a result, by applying a voltage to one upper electrode 44, it becomes possible to apply pressure only to the pressurizing chamber 21 corresponding to the upper electrode 44, and each pressurizing chamber 21 is controlled separately. Can be done.

  Next, the operation of the inkjet head 1 will be described.

  Each pressurizing chamber 21 is prefilled with ink. In this state, an oscillation circuit (not shown) of the control unit applies a pulse voltage of 20 V to the upper electrode 44 corresponding to the nozzle hole 11 where ink is to be ejected, based on the image data.

  By applying a voltage pulse from the upper electrode 44 to the electromechanical conversion element 40, the electromechanical conversion film 43 is instantaneously contracted in a direction parallel to the diaphragm 30 by the electrostrictive effect. As a result, the vibration plate 30 bends toward the inside of the pressurizing chamber 21, the pressure in the pressurizing chamber 21 rises rapidly, and ink is ejected from the nozzle hole 11 communicating with the pressurizing chamber 21.

  After application of the pulse voltage, the contracted electromechanical conversion film 43 returns to its original shape, so that the deflected diaphragm 30 also returns to its original shape. For this reason, the inside of the pressurizing chamber 21 becomes a negative pressure compared to the inside of the common liquid chamber 22, and the ink is supplied from the common liquid chamber 22 through the fluid resistance passage 23 into the pressurizing chamber 21.

  By repeating the above operation, ink droplets can be ejected continuously. Then, an image is formed on a recording medium disposed facing the inkjet head 1.

  Next, a procedure for manufacturing the electromechanical transducer 40 by the method for manufacturing the electromechanical transducer 40 according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4.

  First, an SOI (Silicon On Insulator) substrate is prepared by sequentially laminating a silicon substrate 20, a buried silicon oxide film, and active layer silicon. Then, the surface side of the active layer silicon is processed by a general thermal oxidation method to form a silicon oxide film.

  The thickness of each layer is, for example, 400 μm for the silicon substrate 20, 500 nm for the buried silicon oxide film, 2 μm for the active layer silicon, and 300 nm for the silicon oxide film. The buried silicon oxide film, the active layer silicon, and the silicon oxide film constitute a vibration plate 30.

  Here, the lower electrode 41 formed on the surface side of the diaphragm 30 is electrically connected as a common electrode when a signal is input to the electromechanical transducer 40. For this reason, the diaphragm 30 laminated under the lower electrode 41 is an insulator, or if it is a conductor, it needs to be used after being subjected to insulation treatment. Therefore, in this embodiment, the diaphragm 30 is formed of a buried silicon oxide film, an active layer silicon, and a silicon oxide film, all of which are insulators.

  In this embodiment, the vibration plate 30 is formed of a buried silicon oxide film, an active layer silicon, and a silicon oxide film. However, the present invention is not limited to this, and for example, a silicon oxide film, a silicon nitride film, an oxide film is formed. A silicon nitride film or a film in which these films are stacked may be used. As these silicon insulating films, a thermal oxide film or a CVD deposited film is used.

  Alternatively, the diaphragm 30 may be an insulating film made of a ceramic film such as an aluminum oxide film or a zirconia film in consideration of a difference in thermal expansion. These metal oxide films can be formed by a sputtering method.

  Then, the lower electrode 41 is formed on the surface side of the diaphragm 30. First, an oxide electrode 45 is formed on the surface side of the diaphragm 30 by a sputtering method.

  Here, the material of the lower electrode 41 laminated on the oxide electrode 45 needs to be a metal that can form a SAM (Self-Assembled Monolayer) film by heat resistance and reaction with alkanethiol. Although copper and silver can form a SAM film, it is not preferable to use it because it is altered by heat treatment at 500 to 700 ° C. in the atmosphere. Further, gold is not preferable because it can form a SAM film and does not change even by heat treatment at about 500 to 700 ° C., but is disadvantageous for crystallization of the orientation control layer 42 to be laminated.

  In contrast, platinum, rhodium, ruthenium, iridium single metals, and platinum-rhodium and other platinum group elements such as platinum as the main component have excellent reactivity with thiols and can form SAM films. In addition, it is not deteriorated even by heat treatment at about 500 to 700 ° C., and is advantageous for crystallization of the orientation control layer 42 to be laminated.

  Therefore, in the present embodiment, the platinum group electrode 46 is laminated on the surface side of the oxide electrode 45 by sputtering. Also, a laminate of the silicon substrate 20, the vibration plate 30 and the lower electrode 41 is referred to as an orientation control layer pre-formation substrate 25.

  Then, as shown in FIG. 3A, the SAM film 47 is formed on the surface side of the platinum group electrode 46. The SAM film 47 is obtained by immersing the substrate 25 before forming the alignment control layer in an alkanethiol solution.

In the present embodiment, as an alkanethiol solution, an alkanethiol molecule of CH ₃ (CH ₂ ) —SH is dissolved in a general organic solvent such as alcohol, acetone or toluene at a concentration of, for example, several mol / L. Is used.

  The substrate 25 before forming the alignment control layer is immersed in this alkanethiol solution, taken out after a predetermined time, and then the excess molecules are washed by substitution with a solvent and dried. As a result, organic molecules are self-aligned on the surface side of the platinum group electrode 46, and the SAM film 47 is formed. An alkyl group is disposed on the surface side of the SAM film 47. For this reason, the surface side of the SAM film 47 becomes hydrophobic.

  Next, as shown in FIG. 3B, a photoresist 48 is formed in a predetermined pattern by photolithography. Further, as shown in FIG. 3C, the SAM film 47 is removed by dry etching such as oxygen plasma irradiation or UV light irradiation. Then, the photoresist 48 used for processing is removed, and the patterning of the SAM film 47 is finished (surface modification step). That is, in the present embodiment, the SAM film 47 is patterned by photolithography / etching.

  The SAM film 47 thus formed has a contact angle with respect to pure water of, for example, 92 degrees and exhibits hydrophobicity. On the other hand, the surface of the platinum group electrode 46 of the substrate exposed by removing the SAM film 47 has a contact angle with respect to pure water of 5 degrees, for example, and exhibits hydrophilicity.

  Next, as shown in FIG. 3D, a liquid discharge head 50 of the liquid discharge coating apparatus 100 described later discharges droplets of the alignment control layer precursor solution 2 made of sol onto the platinum group electrode 46. The orientation control layer precursor solution 2 is applied by a liquid discharge method using the liquid discharge head 50 (application step).

  As the orientation control layer precursor solution 2, a lead titanate precursor solution containing lead and titanium is used. Here, the lead titanate precursor solution includes at least lead acetate and titanium salts such as alkoxide, chloride, nitrate, acetate. The concentration of the lead titanate precursor is 0.01 mol / L.

  The alignment control layer precursor solution 2 is not applied on the hydrophobic SAM film 47 but only on the hydrophilic platinum group electrode 46 from which the SAM film 47 has been removed. That is, the alignment control layer precursor solution 2 is applied separately by utilizing the surface energy contrast between the hydrophobic surface and the hydrophilic surface.

  Then, as shown in FIG. 3E, the applied orientation control layer precursor solution 2 is subjected to a heat treatment such as drying at 120 ° C., pyrolyzing at 500 ° C., and crystallizing at 700 ° C., for example. (Heat treatment process). Thereby, the alignment control layer 42 is obtained using the sol-gel method, and all the SAM films 47 are removed by the heat treatment (alignment control layer forming step).

  The orientation control layer 42 thus formed has a thickness of 30 nm and the crystal plane orientation is preferentially oriented to (111).

  Then, as shown in FIG. 4A, the PZT pre-formation substrate 25 on which the orientation control layer 42 is formed is immersed in the alkanethiol solution. The components and concentration of the alkanethiol liquid are the same as those at the time of forming the orientation control layer 42.

  After the PZT pre-formed substrate 25 is taken out after a predetermined time, the surplus molecules are washed by substitution with a solvent and dried. As a result, organic molecules are self-aligned on the surface side of the platinum group electrode 46, and the SAM film 47 is formed.

  Here, the SAM film 47 is not formed on an oxide thin film such as a lead titanate film. Therefore, the SAM film 47 is formed only on the exposed surface side of the platinum group electrode 46 which is a portion other than the portion where the orientation control layer 42 is formed.

  Thereby, the SAM film 47 is formed in a desired pattern without forming the photoresist 48 having a predetermined pattern as shown in FIG. Therefore, the processing procedure can be simplified as compared with the formation of the SAM film 47 when forming the orientation control layer 42.

  4B, liquid droplets of a PZT precursor solution 49 made of sol are discharged onto the alignment control layer 42 by a liquid discharge head 50 of the liquid discharge coating apparatus 100 described later. The PZT precursor solution 49 is applied by a liquid discharge method using the liquid discharge head 50.

  Here, the PZT precursor solution 49 is not applied onto the hydrophobic SAM film 47, and the PZT precursor solution 49 is applied only to the hydrophilic orientation control layer 42 from which the SAM film 47 has been removed. become. That is, the PZT precursor solution 49 is applied separately using the surface energy contrast between the hydrophobic surface and the hydrophilic surface.

  Then, as shown in FIG. 4 (c), the applied PZT precursor solution 49 is dried at, for example, 120 ° C., thermally decomposed at, for example, 500 ° C., and finally crystallized at, for example, 700 ° C. . Thereby, the electromechanical conversion film 43 is obtained by using the sol-gel method, and all the SAM films 47 are removed by the heat treatment (electromechanical conversion film forming step).

  Further, a platinum group upper electrode 44 is laminated and formed on the surface side of the electromechanical conversion film 43 by a sputtering method (second electrode forming step). Thereby, the electromechanical conversion element 40 is manufactured.

  Next, the liquid discharge coating apparatus 100 including the film forming liquid discharge head 50 used in the above-described alignment control layer forming step and electromechanical conversion film forming step will be described.

  As shown in FIG. 5, the liquid discharge application apparatus 100 includes a gantry 110, an X-axis drive unit 120, a Y-axis drive unit 130, a Z-axis drive unit 140, and a liquid discharge application unit 150. . The gantry 110 has a flat plate shape, and is provided with a Y-axis driving unit 130 and an X-axis driving unit 120.

  The Y-axis drive unit 130 includes a stage 131 and a Y-axis drive member (not shown). The Y-axis drive member is installed so as to drive the stage 131 in the Y-axis direction.

  On the stage 131, a substrate in which the silicon substrate 20, the diaphragm 30, and the lower electrode 41 are stacked is mounted. Further, the stage 131 includes a suction unit (not shown). The suction means fixes the pre-alignment control layer forming substrate 25 to the stage 131 by negative pressure or static electricity.

  The X-axis drive unit 120 includes an X-axis support member 121 and an X-axis drive member (not shown). The X-axis drive member is supported by the X-axis support member 121 and holds the Z-axis drive unit 140. Thereby, the Z-axis drive means 140 is driven in the X-axis direction.

  The Z-axis drive unit 140 includes a head base 141 and a Z-axis drive member (not shown). The Z-axis drive member is installed so as to drive the head base 141 in the Z-axis direction.

  The liquid discharge application unit 150 includes a liquid discharge head 50 and a supply pipe 151. The liquid discharge application unit 150 is mounted on the head base 141. The alignment control layer precursor solution 2 and the PZT precursor solution 49 are supplied to the liquid discharge head 50 through a supply pipe 151 from a liquid tank (not shown). The liquid ejection head 50 is connected to an ejection drive power supply (not shown).

  As described above, according to the inkjet head 1 of the present embodiment, since the alignment control layer 42 is formed by the sol-gel method using the liquid discharge head 50 in the alignment control layer forming step, the alignment control is performed on the lower electrode 41. When the layer 42 is formed, it is possible to selectively form only necessary portions without forming the entire surface.

  For this reason, the film is not formed on the entire surface of the lower electrode 41 as in the case of employing the vacuum film formation method or the spin film formation method as the conventional method for forming the orientation control layer 42. Photolithography and etching steps are not necessary. Therefore, the operation of forming the alignment control layer 42 is simplified, and the application of the alignment control layer precursor solution 2 to unnecessary portions that have been finally removed in the past can be eliminated, thereby contributing to cost reduction. .

  In addition, since the alignment control layer 42 is formed by the sol-gel method using the liquid discharge head 50, the alignment control layer 42 is formed as compared with the conventional case where the film is formed by vacuum film formation or spin film formation. Thinning can be achieved. Thereby, the degree of orientation of the orientation control layer 42 is increased (see FIG. 10), so that the displacement characteristics of the electromechanical conversion film 43 can be improved.

  Thus, since the displacement characteristic of the electromechanical conversion film 43 can be improved at low cost, the electromechanical conversion element 40 having a large displacement can be obtained at low cost. Therefore, an inexpensive and high-performance inkjet head 1 can be obtained.

  Further, according to the method of manufacturing the electromechanical conversion film according to the present embodiment, the surface modification step is performed before the application of the alignment control layer precursor solution 2, and therefore the alignment control on the surface side of the platinum group electrode 46 is performed. The alignment control layer precursor solution 2 becomes difficult to adhere to a portion other than the portion to which the layer precursor solution 2 is applied. Thereby, the orientation control layer 42 having a desired pattern can be formed with high accuracy.

  Furthermore, an ink jet recording apparatus 5 provided with the ink jet head 1 according to the above-described embodiment of the present invention will be described.

  As shown in FIGS. 6 and 7, the inkjet recording apparatus 5 includes a printing mechanism unit 60 that performs printing on the recording medium P, a paper feeding mechanism unit 70 that feeds the recording medium P, and a recording medium P. A paper discharge mechanism 80 that discharges paper and a recovery unit 90 are provided.

  The printing mechanism 60 includes an inkjet head 1, an ink cartridge 61, a carriage 62, a main guide rod 63, a sub guide rod 64, a main scanning motor 65, a driving pulley 66, a driven pulley 67, and a timing belt. 68.

  Four inkjet heads 1 are provided so as to eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Each inkjet head 1 has a plurality of nozzle holes 11 arranged linearly in the sub-scanning direction, and is mounted on the carriage 62 with the ink droplet ejection direction facing downward.

  In this embodiment, the inkjet head 1 is provided for each color separately. However, the present invention is not limited to this, and one inkjet head 1 having separate nozzle holes 11 for ejecting ink droplets of each color is provided. May be.

  The ink cartridge 61 includes an air port (not shown) that communicates with the air provided above, a supply port (not shown) that supplies ink to the inkjet head 1 provided below, and an ink cartridge that is filled with ink provided inside. A porous body that does not. In the porous body, the ink supplied to the inkjet head 1 is maintained at a slight negative pressure by the capillary force. Thereby, the ink cartridge 61 supplies ink to the inkjet head 1.

  The main guide rod 63 and the sub guide rod 64 are horizontally mounted on left and right side plates (not shown), and hold the carriage 62 slidably in the main scanning direction.

  An ink cartridge 61 is replaceably mounted on the carriage 62. The carriage 62 is slidably fitted to the main guide rod 63 on the rear side (downstream side in the paper conveyance direction) and is slidably mounted on the sub guide rod 64 on the front side (upstream side in the paper conveyance direction). Has been.

  The driving pulley 66 and the driven pulley 67 are disposed at both ends in the main scanning direction. The drive pulley 66 is attached to the main scanning motor 65 and is driven to rotate.

  The timing belt 68 is stretched around the drive pulley 66 and the driven pulley 67. The timing belt 68 is fixed to the carriage 62. By forward / reverse rotation of the main scanning motor 65, the power is reciprocated in the main scanning direction via the drive pulley 66 and the timing belt 68.

  The paper feed mechanism unit 70 includes a paper feed cassette 71, a manual feed tray 72, a paper feed roller 73, a friction pad 74, a guide member 75, a transport roller 76, a transport roller 77, a front end roller 78, a subsidiary roller. A scanning motor 79 and a printing receiving member 81 are provided.

  The paper feed cassette 71 (or a paper feed tray) may be provided at the lower portion of the ink jet recording apparatus 5 and can be loaded with a large number of recording media P taken from the front side. The paper feed cassette 71 can be inserted into and removed from the inkjet recording apparatus 5.

  The manual feed tray 72 can be turned over. By opening the manual feed tray 72, the recording medium P can be manually fed. The paper feed roller 73 and the friction pad 74 separate and supply the recording medium P set in the paper feed cassette 71. The guide member 75 guides the recording medium P.

  The conveyance roller 76 reverses and conveys the fed recording medium P. The conveyance roller 77 is pressed against the peripheral surface of the conveyance roller 76 and sandwiches the recording medium P with the conveyance roller 76. The leading end roller 78 defines the feeding angle of the recording medium P from the conveying roller 76.

  The sub-scanning motor 79 is connected to the conveyance roller 76 through a gear train, and rotates the conveyance roller 76. The printing receiving member 81 is provided corresponding to the movement range of the carriage 62 in the main scanning direction. The printing receiving member 81 guides the recording medium P sent out from the conveying roller 76 on the lower side of the inkjet head 1.

  The paper discharge mechanism 80 includes a conveyance roller 82, a spur 83, a paper discharge roller 84, a spur 85, an upper guide member 86, a lower guide member 87, and a paper discharge tray 88.

  The conveyance roller 82 and the spur 83 are provided on the downstream side of the printing receiving member 81 in the sheet conveyance direction, and are rotationally driven to send the recording medium P in the sheet discharge direction. The paper discharge roller 84 and the spur 85 send the recording medium P to the paper discharge tray 88. The upper guide member 86 and the lower guide member 87 form a paper discharge path from the printing receiving member 81 to the paper discharge tray 88. The paper discharge tray 88 is mounted on the rear side of the inkjet recording apparatus 5.

  The recovery unit 90 recovers the ejection failure of the inkjet head 1 and is provided at a position outside the recording area on the right end side in the moving direction of the carriage 62 in FIG. The recovery unit 90 includes a cap unit (not shown), a suction unit (not shown), and a cleaning unit (not shown).

  The operation of the above-described ink jet recording apparatus 5 will be described below.

  The recording medium P is loaded into the paper feed cassette 71 or the manual feed tray 72. The recording medium P is taken into the ink jet recording apparatus 5 and conveyed to the lower part of the ink jet head 1 by the paper feed mechanism unit 70.

  At the time of printing, the inkjet mechanism 1 is driven by the printing mechanism unit 60 according to the image signal while moving the carriage 62. Thus, ink is ejected onto the stopped recording medium P to record one line, and after the recording medium P is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the recording medium P reaches the recording area, the recording operation of the printing mechanism unit 60 is ended. Then, the paper discharge mechanism 80 discharges the recording medium P to a paper discharge tray 88 mounted on the rear side.

  On the other hand, during printing standby, the carriage 62 is moved to the recovery unit 90, and the inkjet head 1 is capped by the cap unit. Thereby, the nozzle hole 11 can be kept in a wet state, and ejection failure due to ink drying can be prevented. Further, in the middle of recording or the like, ink that is not related to recording is also ejected, so that the viscosity of the ink in all the nozzle holes 11 is made constant and stable ejection performance is maintained.

  Further, when an ink ejection failure occurs, the nozzle hole 11 of the inkjet head 1 is sealed with a cap unit. Then, bubbles and the like are sucked out together with the ink from the nozzle hole 11 through the tube by suction means. As a result, the ink, dust, etc. adhering to the vicinity of the nozzle hole 11 of the nozzle plate 10 are removed by the cleaning means, and the ink ejection failure is recovered.

  The ink sucked by the cleaning means is discharged into a waste ink reservoir (not shown) installed at the lower part of the ink jet recording apparatus 5 and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, according to the inkjet recording apparatus 5 of the present embodiment, since the inkjet head 1 described above is mounted, an inexpensive and high-performance inkjet recording apparatus 5 can be obtained.

  Here, in the method for manufacturing the electromechanical transducer according to this embodiment, the processing of FIGS. 3A to 3E is performed once to obtain the orientation control layer 42 having a predetermined thickness. However, the method for manufacturing an electromechanical transducer according to the present invention is not limited to this. For example, the orientation control layer 42 may be formed in multiple layers by repeating the steps of FIGS. 3C to 3E two or more times to obtain the orientation control layer 42 having a predetermined thickness.

  In this case, the PZT pre-formation substrate 25 on which the orientation control layer 42 shown in FIG. 3E is formed is immersed in an alkanethiol solution, taken out after a predetermined time, and the excess molecules are washed by substitution with a solvent and dried. As a result, organic molecules are self-aligned on the surface side of the platinum group electrode 46, and the SAM film 47 is formed.

  Here, the SAM film 47 is not formed on an oxide thin film like the orientation control layer 42. Therefore, the SAM film 47 is formed only on the exposed surface side of the platinum group electrode 46 which is a portion other than the portion where the orientation control layer 42 is formed.

  As a result, the SAM film 47 is formed in the same pattern as the first alignment control layer 42 without forming the photoresist 48 having a predetermined pattern as shown in FIG. Therefore, the processing procedure can be simplified as compared with the formation of the SAM film 47 when forming the alignment control layer 42 for the first time.

  In this way, the alignment control layer 42 is stacked in multiple layers to increase the film thickness, which is sufficient while suppressing the occurrence of cracks in the alignment control layer 42 as compared with the case where the film is formed thick by a single film formation process. A thick alignment control layer 42 can be obtained.

  In the electromechanical transducer manufacturing method according to the present embodiment, the orientation control layer 42 has a thickness of 30 nm. However, the electromechanical transducer manufacturing method of the present invention is not limited to this. The film thickness of the orientation control layer 42 is preferably 2 nm to 50 nm (see FIG. 10).

  Further, in the method for manufacturing the electromechanical conversion element according to the present embodiment, the concentration of the lead titanate precursor in the orientation control layer precursor solution 2 is set to 0.01 mol / L. However, the manufacturing method is not limited to this. The concentration of the lead titanate precursor in the orientation control layer precursor solution 2 is preferably 0.01 mol / L to 0.15 mol / L.

  If the concentration of the lead titanate precursor in the orientation control layer precursor solution 2 is high, the film thickness to be formed increases. Therefore, the concentration is appropriately set according to the required film thickness. By setting the concentration of the lead titanate precursor in the orientation control layer precursor solution 2 to 0.01 mol / L to 0.15 mol / L, the thickness of the orientation control layer 42 can be set to 2 nm to 50 nm.

  In the method for manufacturing the electromechanical transducer according to the present embodiment, the electromechanical transducer film 43 having a predetermined thickness is obtained by performing the processes of FIGS. 4A to 4C once. However, the method for manufacturing an electromechanical transducer according to the present invention is not limited to this. For example, the processes of FIGS. 4A to 4C may be repeated two or more times to form the electromechanical conversion film 43 in a multilayered manner to obtain the electromechanical conversion film 43 having a predetermined thickness. .

  In this case, the PZT pre-formation substrate 25 on which the electromechanical conversion film 43 shown in FIG. 4C is formed is immersed in the alkanethiol solution, taken out after a predetermined time, and the excess molecules are washed by substitution with a solvent and dried. As a result, organic molecules are self-aligned on the surface side of the platinum group electrode 46, and the SAM film 47 is formed.

  Here, the SAM film 47 is not formed on an oxide thin film like the electromechanical conversion film 43. Therefore, the SAM film 47 is formed only on the exposed surface side of the platinum group electrode 46 which is a part other than the part where the electromechanical conversion film 43 is formed. Thereby, the SAM film 47 is formed in the same pattern as the SAM film 47 formed immediately before, without forming the photoresist 48 having a predetermined pattern as shown in FIG.

  In this way, by increasing the thickness of the electromechanical conversion film 43 in multiple layers, the generation of cracks in the electromechanical conversion film 43 is suppressed as compared with the case where the film is thickly formed by a single film formation process. Also, a sufficiently thick electromechanical conversion film 43 can be obtained. The thickness of the electromechanical conversion film 43 can be formed to about 5 μm, for example (see Example 9).

  Further, in the method of manufacturing the electromechanical transducer according to this embodiment, as a pattern forming method of the SAM film 47, a photolithography etching method is employed as shown in FIGS. 3 (a) to 3 (c). However, the method for manufacturing an electromechanical transducer according to the present invention is not limited to this. For example, a photolithography resist cover method or an exposure removal method can be employed.

  When the photolithography resist cover method is adopted as the pattern forming method of the SAM film 47, a photoresist pattern is formed on the pattern forming portion on the surface side of the platinum group electrode 46. Then, the SAM film 47 is formed by immersing the substrate 25 before forming the alignment control layer in an alkanethiol solution. At this time, the SAM film 47 is not formed on the photoresist. Then, the SAM film 47 can be patterned by removing the photoresist (see Example 2).

  When the exposure removal method is adopted as the pattern forming method of the SAM film 47, the substrate 25 before forming the alignment control layer is immersed in the alkanethiol solution to form the SAM film 47 on the entire surface, as in FIG. . Then, a mask is provided in a portion other than the pattern forming portion of the SAM film 47, and ultraviolet rays are irradiated. As a result, the SAM film 47 remains in the portion where the mask is provided, and the SAM film 47 disappears in the exposed portion where the mask is not masked. As a result, the SAM film 47 can be patterned (see Example 3).

  Further, in the method for manufacturing the electromechanical transducer according to the present embodiment, the surface modification other than the predetermined portion on which the alignment control layer precursor solution 2 is applied on the lower electrode 41 is made a hydrophobic surface by the SAM film 47. However, the method for manufacturing the electromechanical transducer according to the present invention is not limited to this. For example, when the surface of the lower electrode 41 is a hydrophobic surface, surface modification may be performed so that the surface of a predetermined portion to which the orientation control layer precursor solution 2 on the lower electrode 41 is applied is a hydrophilic surface. .

  Further, in the method for manufacturing the electromechanical conversion film according to the present embodiment, the surface modification step is performed before the application of the alignment control layer precursor solution 2, but in the method for manufacturing the electromechanical conversion film of the present invention, However, the surface modification step may be omitted.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

Example 1
A thermal oxide film (film thickness 1 μm) was formed on a silicon substrate 20 made of a silicon wafer, and a titanium film (film thickness 50 nm) was formed thereon as an adhesion layer by sputtering. Further, a platinum group electrode 46 (film thickness: 200 nm) was formed by sputtering as the lower electrode 41 to obtain the substrate 25 before forming the orientation control layer. As shown in FIG. 13, the contact angle of pure water on the surface side of the platinum group electrode 46 was 5 °, and it was in a completely wet state.

Then, using a _CH 3 _(CH 2) -SH as alkanethiol to yield a solution having a concentration of 0.01 mol / L of solvent with isopropyl alcohol. The substrate 25 before forming the orientation control layer was immersed in this solution, and SAM film formation processing was performed. After the substrate 25 before forming the orientation control layer was taken out of the solution, the substrate 25 before forming the orientation control layer was washed with isopropyl alcohol and dried.

  As shown in FIG. 12, the contact angle of pure water on the surface side of the platinum group electrode 46 was 92.2 °, which was a hydrophobic state. This revealed that the SAM film 47 was formed (FIG. 3A).

  Photoresist (Tokyo Ohka Co., Ltd. (TSMR8800)) 48 is formed on the SAM film 47 by spin coating, and a resist pattern is formed in a portion where the orientation control layer 42 is not formed by known photolithography (FIG. 3). (B)). Further, an exposed portion of the SAM film 47 was removed by performing oxygen plasma treatment. The treated photoresist 48 was dissolved and removed with acetone (FIG. 3C). And the contact angle evaluation of the pure water was performed.

  As a result, the contact angle of the removed portion of the SAM film 47 was about 5 ° (complete wetting), and the contact angle of the portion covered with the photoresist 48 was 92.4 °. Therefore, it was confirmed that the SAM film 47 was patterned.

(Example 2)
Similarly to Example 1, the silicon substrate 20, the thermal oxide film, the titanium film, and the platinum group electrode 46 were laminated to obtain the substrate 25 before forming the orientation control layer.

  A photoresist (Tokyo Ohka Kogyo Co., Ltd. (TSMR8800)) was formed on the surface of the platinum group electrode 46 by spin coating, and a resist pattern was formed on the portion where the orientation control layer 42 was to be formed by known photolithography.

  Subsequently, the substrate 25 before alignment control layer formation was immersed in the same alkanethiol solution as in Example 1, and a SAM film formation process was performed. After the substrate 25 before forming the orientation control layer was taken out of the solution, the substrate 25 before forming the orientation control layer was washed with isopropyl alcohol and dried. Then, the photoresist was dissolved and removed with acetone. Furthermore, contact angle evaluation of pure water was performed.

  As a result, the contact angle of the portion covered with the photoresist was about 5 ° (complete wetting), and the contact angle was 92.0 ° in the other portions. Therefore, it was confirmed that the SAM film was patterned.

(Example 3)
Similarly to Example 1, the silicon substrate 20, the thermal oxide film, the titanium film, and the platinum group electrode 46 were laminated to obtain the substrate 25 before forming the orientation control layer.

  Subsequently, the substrate 25 before alignment control layer formation was immersed in the same alkanethiol solution as in Example 1, and a SAM film formation process was performed. After the substrate 25 before forming the orientation control layer was taken out of the solution, the substrate 25 before forming the orientation control layer was washed with isopropyl alcohol and dried.

  The SAM film 47 formed on the platinum group electrode 46 was irradiated with ultraviolet rays while masking a portion where the orientation control layer 42 was not formed. The ultraviolet rays were irradiated for 10 minutes as vacuum ultraviolet rays having a wavelength of 176 nm by an excimer lamp. Furthermore, contact angle evaluation of pure water was performed.

  As a result, the contact angle was about 5 ° (complete wetting) in the ultraviolet irradiated portion, and the contact angle of the portion covered with the mask was 92.2 °. Therefore, it was confirmed that the SAM film was patterned.

Example 4
The alignment control layer precursor solution 2 was synthesized using isopropoxide titanium as a starting material. Isopropoxide titanium was dissolved in methoxyethanol, and an alcohol exchange reaction was performed to obtain a solution. On the other hand, lead acetate, zirconium alkoxide, and titanium alkoxide compounds were used as starting materials and dissolved in methoxyethanol as a common solvent to obtain a uniform solution.

  Furthermore, a lead titanate precursor solution was synthesized as the orientation control layer precursor solution 2 by mixing these two solutions. The isopropoxide titanium concentration was 0.01 mol / L.

  Using the liquid discharge coating apparatus 100 shown in FIG. 5, the alignment control layer precursor solution 2 is applied to the surface side of the patterned platinum group electrode 46 of the SAM film 47 obtained in Example 1 by the liquid discharge head 50. It was applied once (FIG. 3 (d)). Thereby, the orientation control layer precursor solution 2 was applied only to the hydrophilic portion where the SAM film 47 was not formed.

  Further, the applied orientation control layer precursor solution 2 was dried at 120 ° C. and thermally decomposed at 500 ° C. (FIG. 3E).

  As a result, an orientation control layer 42 having a thickness in the short direction center part of 2 nm and a thickness in the short direction end part of 1.2 nm was obtained. Therefore, it was confirmed that a thin alignment control layer 42 that could not be obtained by the spin coating method was obtained.

(Example 5)
After the surface side of the sample on which the orientation control layer 42 obtained in Example 4 was formed was washed with isopropyl alcohol, the sample was immersed in the same alkanethiol solution as in Example 1 to perform SAM film formation processing. . After removing the sample from the solution, it was washed with isopropyl alcohol and dried.

  The contact angle of the orientation control layer 42 was about 5 ° (complete wetting), and the contact angle of the portion where the orientation control layer 42 was exposed was 92.0 °. Thereby, formation of the self-aligned SAM film 47 was confirmed (FIG. 4A).

(Example 6)
A PZT precursor solution 49 was applied by the liquid discharge head 50 to the surface side of the patterned sample of the SAM film 47 obtained in Example 5 using the liquid discharge application apparatus 100 shown in FIG. 5 (FIG. 4). (B)). As a result, the PZT precursor solution 49 was applied only to the hydrophilic portion where the SAM film 47 was not formed, that is, the orientation control layer 42.

  The PZT precursor solution 49 used lead acetate trihydrate, isopropoxide titanium, and normal butoxide zirconium as starting materials. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. In order to prevent crystallinity deterioration due to so-called lead loss during the heat treatment, the lead amount was excessive by 10 mol% with respect to the stoichiometric composition.

  Isopropoxide titanium and normal butoxide zirconium were dissolved in methoxyethanol, and alcohol exchange reaction and esterification reaction were advanced. And the PZT precursor solution 49 was synthesize | combined by mixing uniformly with the methoxyethanol solution which melt | dissolved the lead acetate mentioned above.

  The film thickness obtained by a single film formation is preferably 100 nm or less in order to prevent generation of cracks during crystallization. For this reason, it is preferable to adjust the precursor concentration of the PZT precursor solution 49 so as to be optimized from the relationship between the deposition area of the electromechanical conversion film 43 and the coating amount of the PZT precursor solution 49. In this example, the PZT concentration of the PZT precursor solution 49 was set to 0.1 mol / L. However, it is needless to say that it is not limited to 0.1 mol / L.

Here, PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ), and the characteristics differ depending on the ratio. The compositions shown generally excellent piezoelectric characteristics at a ratio of ratio of PbZrO ₃ and PbTiO ₃ is 53:47, Pb (Zr0.53, Ti0.47) O 3, generally indicated as PZT (53/47). The starting materials for lead acetate, zirconium alkoxide and titanium alkoxide compounds are weighed according to this chemical formula.

  Further, 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 may be added to the precursor solution as a stabilizer.

  In this embodiment, the PZT precursor solution 49 is selectively used by the surface modification step (FIG. 4A) for partially forming the SAM film 47 on the sample and the liquid discharge head 50 of the liquid discharge coating apparatus 100. A coating step (FIG. 4 (b)) to be applied to the substrate, a drying step (FIG. 4 (c)) to dry the applied PZT precursor solution 49 at a predetermined temperature (120 ° C.), and a dried PZT precursor solution 49 to A pyrolysis step (FIG. 4C) in which pyrolysis is performed at a predetermined temperature (500 ° C.) was performed once.

  Thereby, a film having a thickness of 80 nm was obtained on the surface side of the orientation control layer 42. And the film | membrane with a film thickness of 540 nm was obtained by repeating the surface modification process, application | coating process, drying process, and thermal decomposition process which were mentioned above 6 times. Further, crystallization heat treatment at 700 ° C. was performed on the obtained film having a thickness of 430 nm by rapid heat treatment (RTA).

  As a result, an electromechanical conversion film 43 having a film thickness of 540 nm was obtained on the surface side of the orientation control layer 42. No defects such as cracks occurred in the electromechanical conversion film 43. Further, due to the formation of the SAM film 47, there was no occurrence of a pattern defect in which the PZT precursor solution 49 was applied in addition to the necessary pattern forming portion.

(Example 7)
The electromechanical conversion film 43 having a film thickness of 540 nm obtained in Example 6 was further processed. Here, the same surface modification step, coating step, drying step (120 ° C.), and thermal decomposition step (500 ° C.) as described above were repeated six times, and then the crystallization treatment was performed for two cycles.

  As a result, a patterned electromechanical conversion film 43 having a thickness of 1000 nm was obtained. No defects such as cracks occurred in the electromechanical conversion film 43.

(Example 8)
The electromechanical conversion film 43 having a film thickness of 1000 nm obtained in Example 7 was further processed. Here, the upper electrode 44 made of platinum was formed on the electromechanical conversion film 43 by sputtering, and the electrical characteristics and the electromechanical conversion ability (piezoelectric constant) were evaluated.

As a result, regarding the electrical characteristics, a hysteresis curve of P (polarization) -E (electric field strength) shown in FIG. 8 was obtained. The electromechanical conversion film 43 had a relative dielectric constant of 1220, a dielectric loss of 0.02, a remanent polarization of 22.3 μC / cm ² , and a coercive electric field of 31.5 kV / cm. Therefore, it was found that the electromechanical conversion film 43 has electric characteristics equivalent to those of a normal ceramic sintered body.

  In addition, the electro-mechanical conversion ability was calculated by measuring the amount of deformation by applying an electric field with a laser Doppler vibrometer and fitting by simulation. As a result, the piezoelectric constant d31 was −120 pm / V. Therefore, the electromechanical conversion film 43 has a value equivalent to that of the ceramic sintered body in the electromechanical conversion ability. This value is a characteristic value that is sufficiently applicable as an electromechanical conversion film (piezoelectric element) used in a general inkjet head.

Further, this electromechanical conversion film 43 was subjected to XRD analysis. As a result, as shown in FIG. 9, the (111) orientation degree was 91%. For this reason, the preferential orientation of the plane orientation (111) was confirmed. In addition, the orientation ratio is expressed as Equation 1.
[Equation 1]
(111) Degree of orientation = ΣI (111) / ΣI (hkl) (where h, k, and l are arbitrary values)

  From these things, it became clear that this electromechanical conversion film 43 is sufficiently applicable as an electromechanical conversion film used for a general inkjet head.

Example 9
The electromechanical conversion film 43 having a film thickness of 1000 nm obtained in Example 7 was further processed. Here, an attempt was made to further increase the thickness of the electromechanical conversion film 43 without arranging the upper electrode 44. Specifically, the above-described surface modification step, coating step, drying step (120 ° C.), pyrolysis step (500 ° C.) and the subsequent crystallization treatment are repeated 10 times as a set. It was.

  As a result, a patterned electromechanical conversion film 43 having a thickness of 5 μm was obtained. No defects such as cracks occurred in the electromechanical conversion film 43. Thereby, it became clear that the electromechanical conversion film 43 can be sufficiently thickened as necessary.

(Example 10)
In order to increase the film thickness of the orientation control layer 42, (1) increase the solid content concentration of the orientation control layer precursor solution 2, and (2) apply and heat-treat the orientation control layer precursor solution 2 a plurality of times. There are two methods.

  In this example, the film thickness of the orientation control layer 42 was increased using the method (1). Orientation control layer precursor solutions 2 having different solid content concentrations in several stages were prepared, and coating and heat treatment were performed on each. Then, a plurality of orientation control layers 42 having a short-side direction center film thickness of 25, 50, 75, and 100 nm were obtained. Then, an electromechanical conversion film 43 was formed on all the obtained orientation control layers 42 in the same manner as in Example 6.

  Each electromechanical conversion film 43 was subjected to XRD analysis. As a result, as shown in FIG. 10, the film thickness of the orientation control layer 42 was 50 nm or less, and the (111) orientation degree was 90% or more. When the orientation control of the electromechanical conversion film 43 is performed, the orientation degree is preferably 90% or more. For this reason, in this example, the orientation degree requirement was satisfied when the orientation control layer 42 had a thickness of 50 nm or less. Thereby, it was found that the film thickness of the orientation control layer 42 is preferably 2 nm to 50 nm, and most preferably about 30 nm including an error.

  Further, the electromechanical conversion film 43 formed on the alignment control layer 42 having a film thickness of 50 nm having the highest degree of orientation (95%) was further processed. Here, the upper electrode 44 made of platinum was formed on the electromechanical conversion film 43 by sputtering, and the electrical characteristics were evaluated.

As a result, regarding the electrical characteristics, a hysteresis curve of P (polarization) -E (electric field strength) shown in FIG. 11 was obtained. The electromechanical conversion film 43 had a relative dielectric constant of 1280, a dielectric loss of 0.02, a residual polarization of 24.2 μC / cm ² , and a coercive electric field of 32.5 kV / cm. Therefore, it was found that the electromechanical conversion film 43 has electric characteristics equivalent to those of a normal ceramic sintered body.

  As described above, according to the present invention, since the alignment control layer is formed by the sol-gel method using the liquid discharge head, only a necessary portion is patterned without forming the entire surface when forming the alignment control layer. And a method of manufacturing an electromechanical conversion element capable of forming a thin alignment control layer, an electromechanical conversion element manufactured by the manufacturing method, an ink jet head using the same, and an ink jet recording apparatus. For example, it is effective for all ink jet recording apparatuses used in image recording apparatuses such as printers, copying machines, and facsimile machines.

1 Inkjet head 2 Orientation control layer precursor solution (lead titanate precursor solution)
5 Inkjet recording device 40 Electromechanical transducer 41 Lower electrode (first electrode)
42 orientation control layer 43 electromechanical conversion film 44 upper electrode (second electrode)
46 Platinum group electrode (substrate)
50 Liquid discharge head

JP 2009-255532 A

Claims (4)

In the method of manufacturing an electromechanical conversion element for manufacturing an electromechanical conversion element formed by laminating a first electrode, an orientation control layer, an electromechanical conversion film, and a second electrode on a substrate,
A first electrode forming step of forming the first electrode made of a platinum group alloy on the surface side of the substrate;
An alignment control layer forming step of forming the alignment control layer on the surface side of the first electrode;
An electromechanical conversion film forming step of forming the electromechanical conversion film on the surface side of the orientation control layer;
On the surface side of the electro-mechanical conversion film, Bei example a second electrode forming step of forming the second electrode,
The alignment control layer forming step includes
Surface modification for applying surface modification for inhibiting adhesion of the orientation control layer precursor solution to a second portion other than the first portion to which the orientation control layer precursor solution is applied on the surface side of the first electrode. Process,
Opposite the nozzle of the surface modification step of the surface side of the first electrode surface modification has been performed by the liquid discharge head on the first portion surface modification is not applied by the surface modification step And applying the alignment control layer precursor solution to the first portion of the first electrode by discharging the alignment control layer precursor solution made of sol from the nozzle;
A heat treatment step of heat-treating the orientation control layer precursor solution applied to the first portion of the first electrode by the application step and crystallizing the first electrode on the first electrode to form the orientation control layer; ,
By applying the surface modification to the surface side of the first electrode on which the orientation control layer of oxide is formed, the second portion other than the first portion on which the orientation control layer is formed is formed. A second surface modification step for surface modification;
The nozzle of the liquid ejection head is made to face the first portion where the orientation control layer is formed on the surface side of the first electrode that has been surface-modified by the second surface modification step. A second coating step of coating the PZT precursor solution on the surface of the orientation control layer by discharging a PZT precursor solution made of sol from the nozzle;
A second heat treatment step of forming the electromechanical conversion film by heat-treating and crystallizing the PZT precursor solution applied in the second application step;
Method for manufacturing electromechanical transducer, characterized by have a. Electromechanical transducer, characterized in that manufactured by the manufacturing method of electromechanical transducer of claim 1 described above. An ink-jet head comprising the electromechanical transducer according to claim 2 . An inkjet recording apparatus comprising the inkjet head according to claim 3 .