JP6028419B2 - Electromechanical conversion element and method for manufacturing the same - Google Patents

Description

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

  Regarding an inkjet recording apparatus and a droplet discharge head used as an image recording apparatus or an image forming apparatus such as a printer, a facsimile machine, and a copying apparatus, a nozzle that discharges ink droplets and a pressure chamber (an ink flow path, Pressure chambers, pressure chambers, discharge chambers, liquid chambers, etc.), electromechanical transducers such as piezoelectric elements that pressurize ink in the pressurized chambers, electrothermal transducers such as heaters, or ink flow A structure that includes a diaphragm that forms a wall surface of the road and an energy generating means that includes electrodes facing the diaphragm, and that discharges ink droplets from the nozzles by pressurizing ink in the pressurizing chamber with the energy generated by the energy generating means. It has been known.

  In the manufacturing process of the electromechanical conversion element, for example, a patterned oxide film is formed on a metal film to produce a first electrode, and a PZT film as an electromechanical conversion film is formed only on the oxide film. Then, the second electrode is patterned on the PZT film. By forming the PZT film only on the oxide film, diffusion of Pb contained in the PZT film into the metal film is suppressed (for example, see Patent Document 1).

  However, in the manufacturing method as described above, when the oxide film is patterned, the metal film is over-etched, and the metal film tends to be thin. This tendency is particularly remarkable when the oxide film is a material having a slower etching rate than the metal film. In addition, when the metal film is over-etched in the etching for patterning the second electrode, the metal film is further thinned to increase the resistance value of the first electrode and increase the variation in resistance value. There was a problem. If the metal film is formed thick, this problem can be avoided, but it has been a problem in terms of cost.

  This invention is made | formed in view of said point, and makes it a subject to provide the electromechanical conversion element etc. which can prevent the resistance value of a 1st electrode (lower electrode) becoming high.

  The electromechanical transducer includes a first electrode having a first layer and a second layer formed around a predetermined region on the first layer, and the predetermined electrode on the first layer. The region has an electromechanical conversion film formed so as to protrude from the second layer, and a second electrode formed on the electromechanical conversion film, and the second layer includes the second layer It is a requirement that the layer structure be the same as that of the second electrode.

  According to the disclosed technology, it is possible to provide an electromechanical conversion element or the like that can prevent the resistance value of the first electrode (lower electrode) from increasing.

It is sectional drawing which illustrates the electromechanical conversion element which concerns on 1st Embodiment. FIG. 6 is a diagram (part 1) illustrating a manufacturing process of the electromechanical transducer according to the first embodiment; FIG. 6 is a second diagram illustrating a manufacturing process of the electromechanical transducer according to the first embodiment; FIG. 6 is a third diagram illustrating a manufacturing process of the electromechanical transducer according to the first embodiment; It is a perspective view which illustrates an inkjet coating device. It is a figure which illustrates the manufacturing process of the electromechanical conversion element which concerns on a comparative example. It is a figure for demonstrating the formation precision of a resist layer. It is a figure which illustrates the manufacturing process of the electromechanical conversion element which concerns on the modification of 1st Embodiment. It is sectional drawing which illustrates the droplet discharge head using the electromechanical conversion element which concerns on 1st Embodiment. FIG. 10 is a cross-sectional view illustrating an example in which a plurality of droplet discharge heads of FIG. 9 are arranged. It is a perspective view which illustrates an inkjet recording device. It is a side view which illustrates the mechanism part of an inkjet recording device. FIG. 5 is a characteristic diagram showing a representative electric field strength and a hysteresis curve of polarization.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<First Embodiment>
[Structure of electromechanical transducer according to first embodiment]
In the first embodiment, an example of an electromechanical transducer is shown. First, the structure of the electromechanical conversion element will be described. FIG. 1 is a cross-sectional view illustrating an electromechanical transducer according to the first embodiment. Referring to FIG. 1, the electromechanical conversion element 1 includes a first electrode 11, an electromechanical conversion film 13, and a second electrode 14. Note that the first electrode 11 and the second electrode 14 may be referred to as a lower electrode and an upper electrode, respectively.

  The first electrode 11 includes a first metal film 11a, a first conductive oxide film 11b, a second conductive oxide film 11c, and a second metal film 11d. The first metal film 11a is formed on a substrate such as silicon (not shown), for example, and has a protrusion at the center. As a material of the first metal film 11a, for example, a metal capable of forming a SAM (Self Assembled Monolayer) film by reaction with alkanethiol can be used.

  Specifically, platinum group metals such as ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) and platinum (Pt) having low reactivity, and these platinum group metals An alloy material containing can be used. The thickness of the first metal film 11a can be set to, for example, about 250 nm (thickness including the protruding portion). The protrusion amount of the protrusion portion of the first metal film 11a can be set to, for example, about 50 nm.

A first conductive oxide film 11b is formed on the protruding portion of the first metal film 11a. The material of the first conductive oxide film 11b is described by, for example, the chemical formula ABO ₃ , where A is one or more of Sr, Ba, Ca, and La, and B is any one of Ru, Co, and Ni. A composite oxide containing two or more main components can be used.

Specifically, SrRuO ₃ and CaRuO ₃ , their solid solutions (Sr _1-x Ca _x ) RuO ₃ , LaNiO ₃ and SrCoO ₃ , and their solid solutions (La, Sr) (Ni _1-y Co _y ) O ₃ (y = 1 may be used). Other oxide materials include IrO ₂ and RuO ₂ . The thickness of the first conductive oxide film 11b can be about 50 nm, for example.

  By using the above material for the first conductive oxide film 11b, the possibility that Pb diffuses into the first electrode 11 can be reduced even when the electromechanical conversion film 13 contains Pb. That is, deterioration of the first electrode 11 due to Pb diffusion can be prevented.

  A second conductive oxide film 11c is formed around the protrusion of the first metal film 11a (on the first metal film 11a exposed from the first conductive oxide film 11b). The material of the second conductive oxide film 11c can be appropriately selected from the materials of the first conductive oxide film 11b described above. However, the material of the second conductive oxide film 11c may be the same as or different from the material of the first conductive oxide film 11b. The thickness of the second conductive oxide film 11c can be set to, for example, about 50 nm.

  A second metal film 11d is formed on the second conductive oxide film 11c. The material of the second metal film 11d can be appropriately selected from the materials of the first metal film 11a. However, the material of the second metal film 11d may be the same as or different from the material of the first metal film 11a. The thickness of the second metal film 11d can be set to, for example, about 150 nm.

An electromechanical conversion film 13 is formed on the first conductive oxide film 11b of the first electrode 11 so as to protrude from the second metal film 11d. As a material of the electromechanical conversion film 13, for example, PZT can be used. PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ). For example, the ratio of PbZrO ₃ and PbTiO ₃ is 53:47, and the chemical formula indicates Pb (Zr _0.53 , Ti _0.47 ) O ₃ , PZT generally indicated as PZT (53/47), etc. Can be used. The characteristics of PZT vary depending on the ratio of PbZrO ₃ and PbTiO ₃ .

When PZT is used as the electromechanical conversion film 13, for example, lead acetate, a zirconium alkoxide compound, or a titanium alkoxide compound is used as a starting material, and dissolved in methoxyethanol as a common solvent to prepare a precursor solution of PZT. The mixing amount of the lead acetate, zirconium alkoxide compound, and titanium alkoxide compound can be appropriately selected by those skilled in the art depending on the desired composition of PZT (ratio of PbZrO ₃ and PbTiO ₃ ).

  Note that the metal alkoxide compound is easily decomposed by moisture in the atmosphere. Therefore, acetylacetone, acetic acid, diethanolamine or the like may be added to the PZT precursor solution as a stabilizer.

  As a material of the electromechanical conversion film 13, for example, barium titanate or the like may be used. 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.

These materials are described by the general formula ABO ₃ and correspond to composite oxides containing A = Pb, Ba, Sr B = Ti, Zr, Sn, Ni, Zn, Mg, and Nb as main components. The specific description is expressed as (Pb _1-x , Ba) (Zr, Ti) O ₃ , (Pb _1-x , Sr) (Zr, Ti) O ₃ , which is the same as Pb of the A site. This is a case where the part Ba or Sr is substituted. Such substitution is possible with a divalent element, and the effect thereof has an effect of reducing characteristic deterioration due to evaporation of lead during heat treatment. The thickness of the electromechanical conversion film 13 can be set to, for example, about 1000 nm.

  A second electrode 14 is formed on the electromechanical conversion film 13. For example, the second electrode 14 is formed in a region excluding the outer edge portion on the electromechanical conversion film 13. The second electrode 14 can have a stacked structure in which a second conductive oxide film 14c and a second metal film 14d are sequentially stacked. For convenience of explanation, the second conductive oxide film 14c has a different symbol from the second conductive oxide film 11c, but these films are simultaneously formed in the same process as described later. Similarly, the second metal film 14d has a different symbol from the second metal film 11d, but these films are simultaneously formed in the same process as described later.

  Therefore, the materials of the second conductive oxide film 14c and the second metal film 14d are the same as the materials of the second conductive oxide film 11c and the second metal film 11d, respectively. The thicknesses of the second conductive oxide film 14c and the second metal film 14d are substantially the same as the thicknesses of the second conductive oxide film 11c and the second metal film 11d, respectively. Thus, the second electrode 14 has the same layer configuration as the second conductive oxide film 11c and the second metal film 11d of the first electrode 11.

  Note that the first electrode 11 may not include the second conductive oxide film 11c. Further, the second electrode 14 may not include the second conductive oxide film 14c.

  As described above, in the electromechanical transducer 1 according to the first embodiment, unlike the conventional electromechanical transducer, on the first metal film 11a exposed from the first conductive oxide film 11b, A second conductive oxide film 11c and a second metal film 11d are stacked. Thereby, since the 1st electrode 11 can be thickened, it can prevent that the resistance value of the 1st electrode 11 becomes high. In addition, the resistance value of the first electrode 11 can be prevented from varying.

Hereinafter, as the first metal film 11a and the second metal film 11d (second metal film 14d), the Pt film, the first conductive oxide film 11b, and the second conductive oxide film 11c ( The case where an SrRuO ₃ film is used as the second conductive oxide film 14c) and a PZT film is used as the electromechanical conversion film 13 will be described as an example.
[Method for Manufacturing Electromechanical Transform Element According to First Embodiment]
Next, a method for manufacturing the electromechanical conversion element will be described. 2-4 is a figure which illustrates the manufacturing process of the electromechanical transducer which concerns on 1st Embodiment. First, in the step shown in FIG. 2A, the substrate 10 is prepared. Since the first electrode 11 serving as a common electrode is formed on the substrate 10 in a process described later, an insulator or a conductor or a semiconductor whose surface is insulated can be used as the substrate 10. As the substrate 10, for example, silicon having an oxide film formed on the surface can be used.

Next, in the process shown in FIG. 2B, a Pt film and a first conductive oxide are formed on the substrate 10 as the first metal film 11a by, for example, a vacuum film formation method such as sputtering or vacuum deposition. SrRuO ₃ films are sequentially stacked as the film 11b. Note that the first metal film 11a and the first conductive oxide film 11b are part of the constituent elements of the first electrode 11 serving as a common electrode.

  Next, in the step shown in FIG. 2C, the resist layer 200 is formed in a predetermined region on the first conductive oxide film 11b by, for example, photolithography. In addition, the predetermined area | region which forms the resist layer 200 is an area | region which forms the electromechanical conversion film 13 in the process mentioned later. Next, in the step shown in FIG. 2D, the first conductive oxide film 11b is etched using the resist layer 200 as a mask, and a portion of the first conductive oxide film not covered with the resist layer 200 is etched. 11b is removed. As a result, the first conductive oxide film 11b is formed on the predetermined region of the first metal film 11a.

The etching rate of the Pt film is about 167 nm / min, the etching rate of the SrRuO ₃ film is about 36 nm / min, and there is an etching rate difference of about 5 times. Therefore, the portion of the first metal film 11a (Pt film) that is not covered with the resist layer 200 is about t = 50 nm than the surface on which the first conductive oxide film 11b (SrRuO ₃ film) is formed. Etched more. Next, in the step shown in FIG. 2E, the resist layer 200 shown in FIG. 2D is removed.

Next, in a step shown in FIG. 2 (f), the first metal film 11a exposed from the first conductive oxide film 11b by surface modification to sparse hydration. Specifically, the first metal film 11a and the first conductive oxide film 11b are immersed in a SAM material made of, for example, a thiol compound (alkane thiol or the like), and the first conductive oxide film 11b is used. The SAM film 12 is self-aligned on the exposed surface of the first metal film 11a. As the alkanethiol, for example, CH3 (CH2) -SH or the like can be used. The SAM material is not formed on the first conductive oxide film 11b, but is formed only on the first metal film 11a exposed from the first conductive oxide film 11b.

  Thus, the region where the SAM film 12 is formed (on the first metal film 11a) becomes a hydrophobic portion, and the region where the SAM film 12 is not formed (on the first conductive oxide film 11b) is a hydrophilic portion. Become. For example, the contact angle with respect to pure water of the region where the SAM film 12 is formed (on the first metal film 11a) is 92 degrees, indicating hydrophobicity, and the region where the SAM film 12 is not formed (first conductive oxidation). The contact angle of pure water on the material film 11b is 54 degrees, indicating hydrophilicity.

  As described above, since the wettability contrast is increased by forming the SAM film 12, it is possible to improve the coating accuracy when the PZT precursor solution 13x is applied by an inkjet method in a process described later.

  Here, the ink jet coating apparatus 60 used after the step shown in FIG. FIG. 5 is a perspective view illustrating an inkjet coating apparatus. In the inkjet coating apparatus 60 shown in FIG. 5, a Y-axis driving unit 62 is installed on a gantry 61, and a stage 64 on which a substrate 63 is mounted is installed so as to be driven in the Y-axis direction. The stage 64 is attached with suction means such as vacuum and static electricity not shown, and the substrate 63 is fixed.

  An X-axis drive means 66 is attached to the X-axis support member 65, and a head base 68 mounted on the Z-axis drive means 67 is attached to the X-axis support member 65, so that it can move in the X-axis direction. ing. An ink jet head 69 that discharges ink is mounted on the head base 68. Ink is supplied from an ink tank (not shown) to the inkjet head 69 via a colored resin ink supply pipe 70.

  After the step shown in FIG. 2 (f), in the step shown in FIG. 3 (g) to FIG. A film 13 is formed. First, in the step shown in FIG. 3G, the structure shown in FIG. 2F is placed on the stage 64 of the inkjet coating apparatus 60, and the first conductive oxide film 11b is formed from the inkjet head 69. The PZT precursor solution 13x is applied (on the hydrophilic part). The PZT precursor solution 13 x finally becomes the electromechanical conversion film 13. Thus, the amount of the raw material used for the electromechanical conversion film 13 can be reduced by forming the electromechanical conversion film 13 by the inkjet method.

  Next, in the step shown in FIG. 3H, the PZT precursor solution 13x is heat-treated to form a single-layer electromechanical conversion film 13a. When the ink-jet method is used, the single-layer electromechanical conversion film 13a has a thickness of about 30 to 100 nm. For example, in order to form the 1000 nm electromechanical conversion film 13, FIG. 3 (g) and the process of FIG. 3 (h) are repeated to stack a plurality of single-layer electromechanical conversion films 13a. Thereby, for example, as shown in FIG. 3I, an electromechanical conversion film 13 having a desired film thickness (for example, 1000 nm) is obtained.

Next, in the step shown in FIG. 4 (j), vacuum formation such as sputtering or vacuum deposition is performed on the first metal film 11a exposed around the electromechanical conversion film 13 and on the electromechanical conversion film 13. By a film method or the like, a SrRuO ₃ film is sequentially stacked as the second conductive oxide films 11c and 14c, and a Pt film is sequentially stacked as the second metal films 11d and 14d.

  That is, the second conductive oxide film 11c and the second conductive oxide film 14c are films made of the same material and formed by the same process. Similarly, the second metal film 11d and the second metal film 14d are films made of the same material and formed by the same process. By this step, the first conductive film 11a, the first conductive oxide film 11b, and the second conductive oxide stacked on the first metal film 11a exposed around the electromechanical conversion film 13 are obtained. A first electrode 11 having a film 11c and a second metal film 11d is formed.

  Next, in the step shown in FIG. 4K, for example, the entire region on the second conductive oxide film 11d and the outer edge portion on the second conductive oxide film 14d are removed by photolithography. A resist layer 210 is formed in the region. Next, in the step shown in FIG. 4L, the second conductive oxide film 14c and the second metal film 14d are etched using the resist layer 210 as a mask, and a portion of the portion not covered with the resist layer 210 is etched. The second conductive oxide film 14c and the second metal film 14d are removed. Next, in the step shown in FIG. 4M, the resist layer 210 is removed. By this step, the second electrode 14 including the second conductive oxide film 14c and the second metal film 14d laminated on the electromechanical conversion film 13 is formed, and the electromechanical conversion element 1 is completed. .

  Here, the effect which the electromechanical conversion element 1 which concerns on this Embodiment has is demonstrated using a comparative example. FIG. 6 is a diagram illustrating a manufacturing process of the electromechanical transducer according to the comparative example. First, in the process shown in FIG. 6A, after executing the same processes as in FIGS. 2A to 3I, the first metal film 11a exposed around the electromechanical conversion film 13, and A third metal film is laminated on the electromechanical conversion film 13 by, for example, a vacuum film forming method such as sputtering or vacuum deposition. For convenience, a film laminated on the first metal film 11a exposed around the electromechanical conversion film 13 is referred to as a third metal film 11e, and a film laminated on the electromechanical conversion film 13 is a third metal film. The metal film 14e.

  Next, in the step shown in FIG. 6B, the resist layer 220 is formed in a region excluding the outer edge portion on the third metal film 14e, for example, by photolithography. Next, in the step shown in FIG. 6C, the third metal film 14d is etched using the resist layer 220 as a mask, and the portion of the third metal film 14e not covered with the resist layer 220 and the first metal film 14e are etched. The third metal film 11e formed on the metal film 11a is removed. Thereafter, the resist layer 220 is removed. By this step, the first electrode 11x and the second electrode 14e each including the first metal film 11a and the first conductive oxide film 11b are formed, and the electromechanical conversion element 1x is completed.

  In the process shown in FIG. 6B of the comparative example, since the resist layer 220 is not formed on the third metal film 11e, if the etching stop position is made too late, the first metal film 11a is over-etched, The resistance value of the first electrode 11x may be high. Note that the same problem may occur when the third metal film 11e and the third metal film 14e are formed through the conductive oxide film.

  On the other hand, in the step shown in FIG. 4L of the present embodiment, since the resist layer 210 is also formed on the second conductive oxide film 11d, the second conductive oxide film 11d is overcoated. There is no fear of being etched. Further, even if the first metal film 11a exposed around the electromechanical conversion film 13 is excessively etched in the process shown in FIG. 2D, the second metal film formed in the process shown in FIG. The thickness of the first metal film 11a can be supplemented by the conductive oxide film 11c and the second metal film 11d. As a result, it is possible to prevent the resistance value of the first electrode 11 from increasing. In addition, the resistance value of the first electrode 11 can be prevented from varying.

<Modification of First Embodiment>
In the modification of the first embodiment, another example of the method for manufacturing the electromechanical transducer 1 according to the first embodiment is shown. In the modification of the first embodiment, the description of the same components as those of the already described embodiment is omitted.

  FIG. 7 is a diagram for explaining the formation accuracy of the resist layer. In the process shown in FIG. 4K of the first embodiment, the formation accuracy of the resist layer 210 is poor, and if the resist layer 210 is displaced, the arrangement as shown in FIG. . In this state, when the second conductive oxide film 14c and the second metal film 14d are etched using the resist layer 210 as a mask, as in the step shown in FIG. 4L of the first embodiment, FIG. As shown in FIG. 7B, the film thickness of a part of the first electrode 11 becomes thin, and the resistance value of the first electrode 11 may be increased.

  Therefore, in the modification of the first embodiment, the steps shown in FIGS. 8A and 8B are executed instead of the steps shown in FIGS. 4K to 4M. First, in the step shown in FIG. 8A, the entire region on the second conductive oxide film 11d and the outer edge on the second conductive oxide film 14d are formed by, for example, photolithography. A resist layer 230 is formed in a region excluding the annular region. That is, the resist layer 230 has an opening 230x that exposes an annular region inside the outer edge on the second conductive oxide film 14d.

  Next, in the step shown in FIG. 8B, the second conductive oxide film 14c and the second metal film 14d are etched using the resist layer 230 as a mask to expose the second exposed at the bottom of the opening 230x. The conductive oxide film 14c and the second metal film 14d are removed. Thereafter, the resist layer 230 is removed.

  In the modification of the first embodiment, the areas of the second conductive oxide film 14c and the second metal film 14d constituting the second electrode 14 are the same as those in the first embodiment (FIG. 4). (See (m) etc.). That is, in the modified example of the first embodiment, the portion where the electric field is applied to the electromechanical transducer 13 is smaller than in the case of the first embodiment.

  However, in the step shown in FIG. 8A, even if the resist layer 230 is displaced as shown in FIG. 7A, the opening 230x is located on the second conductive oxide film 14d. As long as the thickness of the first electrode 11 is not reduced, the thickness of the first electrode 11 is not reduced. In other words, in consideration of the formation accuracy of the resist layer 230, the position of the opening 230x is set so that the opening 230x is always located on the second conductive oxide film 14d even if the resist layer 230 is displaced. If designed, the influence of displacement of the resist layer 230 can be reduced.

  As described above, in the modification of the first embodiment, in addition to the effect of the first embodiment, the film thickness of a part of the first electrode is reduced due to the influence of the displacement of the resist layer. There exists an effect which prevents that the resistance value of 1 electrode becomes high.

<Second Embodiment>
In the second embodiment, an example of a droplet discharge head using the electromechanical transducer according to the first embodiment is shown. In the second embodiment, the description of the same components as those of the already described embodiments is omitted.

  FIG. 9 is a cross-sectional view illustrating a droplet discharge head using the electromechanical transducer according to the first embodiment. Referring to FIG. 9, the droplet discharge head 2 includes an electromechanical conversion element 1, a nozzle plate 20, a pressure chamber substrate 30, and a vibration plate 40. The nozzle plate 20 is formed with nozzles 21 that eject ink droplets. The nozzle plate 20, the pressure chamber substrate 30, and the vibration plate 40 may be referred to as a pressure chamber 31 (an ink channel, a pressurized liquid chamber, a pressurized chamber, a discharge chamber, a liquid chamber, or the like) that communicates with the nozzle 21. ) Is formed. The diaphragm 40 forms part of the wall surface of the ink flow path. In FIG. 9, descriptions of the liquid supply means, the flow path, the fluid resistance, and the like are omitted.

The electromechanical conversion element 1 is mounted on the vibration plate 40 via the adhesion layer 50 and has a function of pressurizing ink in the pressure chamber 31. The adhesion layer 50 is a layer made of, for example, Ti, TiO ₂ , TiN, Ta, Ta ₂ O ₅ , Ta ₃ N _{5, and the} like, and adhesion between the first electrode 11 of the electromechanical transducer 1 and the diaphragm 40. It has a function to improve. However, the adhesion layer 50 may be provided as necessary.

  In the electromechanical conversion element 1, when a voltage is applied between the first electrode 11 and the second electrode 14, the electromechanical conversion film 13 is mechanically displaced. Along with the mechanical displacement of the electromechanical conversion film 13, the diaphragm 40 is deformed and displaced, for example, in the lateral direction (d31 direction), and pressurizes the ink in the pressure chamber 31. Thereby, ink droplets can be ejected from the nozzle 21.

  As shown in FIG. 10, a plurality of droplet discharge heads 2 can be arranged in parallel to form the droplet discharge head 3.

  As described above, the electromechanical conversion element 1 according to the first embodiment can be used as, for example, a component of a droplet discharge head used in an inkjet recording apparatus, but is not limited thereto. The electromechanical conversion element 1 according to the first embodiment may be used as a component such as a micropump, an ultrasonic motor, an acceleration sensor, a two-axis scanner for a projector, an infusion pump, or the like.

<Third Embodiment>
In the third embodiment, an example of an ink jet recording apparatus equipped with a droplet discharge head 3 (see FIG. 10) is shown. FIG. 11 is a perspective view illustrating an ink jet recording apparatus. FIG. 12 is a side view illustrating the mechanism unit of the ink jet recording apparatus. The ink jet recording apparatus 4 is a typical example of a droplet discharge apparatus according to the present invention.

  Referring to FIGS. 11 and 12, the inkjet recording apparatus 4 is an inkjet that is an embodiment of a droplet 93 that is movable in the main scanning direction inside the recording apparatus main body 81, and a droplet discharge head 3 mounted on the carriage 93. A printing mechanism 82 including an ink cartridge 95 that supplies ink to the recording head 94 and the ink jet recording head 94 is accommodated.

  A paper feed cassette 84 (or a paper feed tray) on which a large number of sheets 83 can be stacked can be detachably attached to the lower portion of the recording apparatus main body 81. Further, the manual feed tray 85 for manually feeding the paper 83 can be turned over. 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 the carriage 93 slidably in the main scanning direction with 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 has an inkjet recording head 94 that ejects ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk), and a plurality of ink ejection ports (nozzles) in the main scanning direction. They are arranged in the intersecting direction and mounted with the ink droplet ejection direction facing downward. Further, the carriage 93 is mounted with replaceable ink cartridges 95 for supplying ink of each color to the ink jet recording head 94.

  The ink cartridge 95 has an air port (not shown) that communicates with the atmosphere above, an air port (not shown) that supplies ink to the ink jet recording head 94 below, and a porous body (not shown) filled with ink inside. ing. The ink supplied to the inkjet recording head 94 is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the respective color heads are used here as the ink jet recording head 94, one head having nozzles for ejecting ink droplets of each color may be used.

  The carriage 93 is slidably fitted to the main guide rod 91 on the downstream side in the paper conveyance direction, and is slidably mounted on the sub guide rod 92 on the upstream side in the paper conveyance direction. 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 the main scanning motor 97, so that the main scanning motor 97 is forward / reverse. The carriage 93 is reciprocated by the rotation. The timing belt 100 is fixed to the carriage 93.

  Further, the ink jet recording apparatus 4 reverses and feeds the paper feed roller 101 for separating and feeding the paper 83 from the paper feed cassette 84, the friction pad 102, the guide member 103 for guiding the paper 83, and the fed paper 83. A conveyance roller 104, a conveyance roller 105 that is pressed against the circumferential 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 are provided. As a result, the paper 83 set in the paper feed cassette 84 is conveyed to the lower side of the ink jet recording head 94. The transport roller 104 is rotationally driven by a sub-scanning motor 107 through a gear train.

  The printing receiving member 109 which is a paper guide member guides the paper 83 sent out from the conveying roller 104 corresponding to the movement range of the carriage 93 in the main scanning direction on the lower side of the ink jet recording head 94. 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.

  During image recording, the inkjet recording head 94 is driven in accordance with the image signal while moving the carriage 93, thereby ejecting ink onto the stopped paper 83 to record one line and transporting the paper 83 by a predetermined amount. After that, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing end of the paper 83 reaches the recording area, the recording operation is terminated and the paper 83 is discharged.

  A recovery device 117 for recovering defective ejection of the inkjet recording head 94 is provided 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 ink jet 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 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 ejection failure occurs, the ejection port of the ink jet recording head 94 is sealed with a capping unit, and bubbles and the like are sucked out from the ejection port with the suction unit through the tube. Also, ink or dust adhering to the ejection port surface is 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 recording head 94 which is an embodiment of the droplet ejection head 3 is mounted in the inkjet recording apparatus 4, there is no ink droplet ejection failure due to vibration plate drive failure, and stable ink droplet ejection. Since the characteristics can be obtained, the image quality can be improved.

[Example]
In this example, an electromechanical transducer was produced based on the steps described with reference to FIGS. 2 to 4 of the first embodiment. First, on the substrate, a Pt film as a first metal film is formed with a thickness of 250 nm, and a SrRuO ₃ film as a first conductive oxide film is formed with a thickness of 50 nm in sequence by sputtering (FIGS. 2A and 2B). )reference).

Next, the patterned photoresist on the first conductive oxide film (SrRuO ₃ film), a first conductive oxide film other than the region for forming the electro-mechanical conversion film (SrRuO ₃ film) etching (See FIG. 2 (c) to FIG. 2 (e)). As described above, since the etching rate of the Pt film and the SrRuO ₃ film has a difference of a little less than five times, the portion of the first metal film (Pt film) that is not covered with the resist has the first conductive oxidation. Etching was performed 50 nm more than the surface on which the material film (SrRuO ₃ film) was formed.

Next, the first metal film (Pt film) and the first conductive oxide film (SrRuO ₃ film) are immersed in a SAM material made of CH ₃ (CH ₂ ) -SH to obtain a first conductive property. The SAM film was self-aligned on the surface of the first metal film (Pt film) exposed from the oxide film (SrRuO ₃ film) to make it hydrophobic (see FIG. 2 (f)).

Next, an electromechanical conversion film was formed on the first conductive oxide film (SrRuO ₃ film) (see FIGS. 3G to 3I). Specifically, the PZT precursor solution was applied onto the first conductive oxide film (SrRuO ₃ film) (on the hydrophilic portion) by an ink jet method using the ink jet coating apparatus 60 (see FIG. 5). As starting materials for the PZT precursor, lead acetate trihydrate, isopropoxide titanium and isopropoxide zirconium were used. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. The amount of lead was excessive by 10 mol% relative to the stoichiometric composition. This is to prevent crystallinity deterioration due to so-called lead loss during heat treatment.

  Isopropoxide titanium and isopropoxide 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 was 0.1 mol / liter. The film thickness of PZT obtained by a single film formation is preferably about 100 nm, and the precursor concentration of the PZT precursor solution is optimized from the relationship between the film formation area and the amount of precursor applied.

The PZT precursor solution spreads only on the first conductive oxide film (SrRuO ₃ film), which is a hydrophilic portion, and forms a pattern due to the contact angle contrast. This was treated as 120 ° C. as the first heating (solvent drying), and the organic matter was thermally decomposed. The film thickness at this time was 90 nm. Subsequently, after washing with isopropyl alcohol as a repeated treatment, a SAM film was formed by the same immersion treatment. Even in this step, since the SAM film is not formed on the first conductive oxide film (SrRuO ₃ film), the pattern of the SAM film was obtained without performing the photolithography process.

  The contact angle at this time was 92 degrees on the SAM film and 34 degrees on the PZT film with respect to pure water. In this state, alignment was performed on the PZT film formed for the first time, and the PZT precursor solution was applied again by the inkjet coating apparatus 60. Further, the same heating process as that in the first time was performed to obtain a PZT film that was overlaid. The film thickness at this time was 180 nm.

  Such a process was repeated 6 times to obtain a 540 nm PZT film, and then a crystallization heat treatment (temperature 700 ° C.) was performed by RTA (rapid heat treatment). Defects such as cracks did not occur in the film. Further, 6 times of SAM treatment → selective application of PZT precursor solution → 120 ° C. drying → 500 ° C. pyrolysis, followed by crystallization treatment to obtain an electromechanical conversion film (PZT film) having a film thickness of 1000 nm. Defects such as cracks did not occur in the film.

Next, the second conductive oxide is formed on the first metal film (Pt film) exposed around the electromechanical conversion film (PZT film) and the electromechanical conversion film (PZT film) by sputtering. A SrRuO ₃ film as a film was deposited in a thickness of 50 nm, and a Pt film as a second metal film was laminated in a thickness of 150 nm (see FIG. 4J).

Next, on the second conductive oxide film (SrRuO ₃ film) on the first metal film (Pt film) exposed around the electromechanical conversion film (PZT film), and on the electromechanical conversion film (PZT film) A photoresist was applied by spin coating on the second conductive oxide film (SrRuO ₃ film). Then, the photoresist on the outer edge portion of the second conductive oxide film (SrRuO ₃ film) formed on the electromechanical conversion film (PZT film) was removed by photolithography (see FIG. 4K). ).

Next, using the photoresist as a mask, the second conductive oxide film (SrRuO ₃ film) and the second metal film (Pt film) on the electromechanical conversion film (PZT film) are etched and covered with the photoresist. The portion of the second conductive oxide film (SrRuO ₃ film) and the second metal film (Pt film) that are not formed are removed, and the photoresist is further removed to produce a second electrode (FIG. 4 (l)). ) And FIG. 4 (m)). Thus, an electromechanical conversion element was produced on the substrate.

Next, the electrical characteristics and electromechanical conversion ability (piezoelectric constant) of the produced electromechanical transducer were evaluated. The relative dielectric constant of the electromechanical conversion film is 1220, the dielectric loss is 0.02, the remanent polarization is 19.3 μC / cm ² , the coercive electric field is 36.5 kV / cm, and it has the same characteristics as a normal ceramic sintered body. (See FIG. 13 for the PE hysteresis curve).

  The electromechanical conversion ability was calculated by measuring the amount of deformation by applying an electric field with a laser Doppler vibrometer and adjusting by simulation. The produced electromechanical transducer had a piezoelectric constant d31 of 120 pm / V, which was also the same value as the ceramic sintered body. This is a characteristic value that can be sufficiently designed as a droplet discharge head.

  Subsequently, an attempt was made to further increase the thickness of the electromechanical conversion film (PZT film). That is, crystallization treatment is performed every time pyrolysis annealing is performed up to 6 times, and this is repeated 10 times, and a 5 μm patterned electromechanical conversion film (PZT film) is obtained without defects such as cracks. It was.

  The preferred embodiment and its modifications and examples have been described in detail above, but the present invention is not limited to the above-described embodiment and its modifications and examples, and departs from the scope described in the claims. Without departing from the above, various modifications and substitutions can be made to the above-described embodiment and its modifications and examples.

DESCRIPTION OF SYMBOLS 1 Electromechanical conversion element 2, 3 Droplet discharge head 4 Inkjet recording device 10 Substrate 11 1st electrode 11a 1st metal film 11b 1st electroconductive oxide film 11c 2nd electroconductive oxide film 11d 2nd Metal film 12 SAM film 13, 13a Electromechanical conversion film 13x PZT precursor solution 14 Second electrode 14c Second conductive oxide film 14d Second metal film 20 Nozzle plate 21 Nozzle 30 Pressure chamber substrate 31 Pressure chamber 40 Diaphragm 50 Adhesion layer
DESCRIPTION OF SYMBOLS 60 Inkjet coating device 61 Base 62 Y-axis drive means 63 Substrate 64 Stage 65 X-axis support member 66 X-axis drive means 67 Z-axis drive means 68 Head base 69 Inkjet head 70 Colored resin ink supply pipe 81 Recording device main body 82 Printing mechanism Section 83 Paper 84 Paper feed cassette 85 Manual feed tray 86 Paper discharge tray 91 Main guide rod 92 Subordinate guide rod 93 Carriage 94 Inkjet recording head 95 Ink cartridge 97 Main scanning motor 98 Drive pulley 99 Driven pulley 100 Timing belt 101 Feed roller 102 Friction Pad 103 Guide member 104 Conveying roller 105 Conveying roller 106 Leading end roller 107 Sub-scanning motor 109 Printing receiving member 111 Conveying roller 112 Spur 113 Discharge roller 1 4 spurs 115, 116 guide member 117 recovery device 200,210,230 resist layer 230x opening

JP 2012-061702 A

Claims (10)

A first electrode comprising a first layer and a second layer formed around a predetermined region on the first layer;
An electromechanical conversion film formed so as to protrude from the second layer in the predetermined region on the first layer;
A second electrode formed on the electromechanical conversion film,
The electromechanical transducer element in which the second layer has the same layer configuration as the second electrode.   The electromechanical transducer according to claim 1, wherein the first electrode further includes a first conductive oxide film formed between the predetermined region and the electromechanical transducer film. The material of the first conductive oxide film is described by the chemical formula ABO ₃ , wherein A is one or more of Sr, Ba, Ca, and La, and B is one or more of Ru, Co, and Ni. The electromechanical transducer according to claim 2, wherein the electromechanical conversion element is a composite oxide having a main component, or an oxide made of IrO ₂ or RuO ₂ . The first layer is formed of a first metal film;
The said 2nd layer and the said 2nd electrode are the laminated structures in which the 2nd electroconductive oxide film and the 2nd metal film were laminated | stacked one by one, respectively. Electromechanical transducer. The first layer is formed of a first metal film;
4. The electromechanical transducer according to claim 1, wherein each of the second layer and the second electrode is formed of a second metal film.   A liquid droplet ejection head comprising the electromechanical transducer according to claim 1.   A droplet discharge apparatus comprising the droplet discharge head according to claim 6. Forming a first conductive oxide film on a predetermined region of the first metal film;
Forming an electromechanical conversion film on the first conductive oxide film;
Sequentially stacking a second conductive oxide film and a second metal film on the first metal film exposed around the electromechanical conversion film and on the electromechanical conversion film, respectively. Have
In the step of sequentially laminating, the electromechanical conversion film includes a second conductive oxide film and a second metal film formed on the first metal film exposed around the electromechanical conversion film. Also protruding,
The first metal film, the first conductive oxide film, the second conductive oxide film laminated on the first metal film exposed around the electromechanical conversion film, and the The second metal film constitutes the first electrode,
The method for manufacturing an electromechanical conversion element in which the second conductive oxide film and the second metal film stacked on the electromechanical conversion film constitute a second electrode. Step includes a step of sparse hydrating said first metal film by surface modified exposed around the first conductive oxide film forming the electro-mechanical conversion film,
After the step of the sparse hydration method of the first electromechanical conversion element according to claim 8, wherein the conductive oxide film and forming an electro-mechanical transducer film by an ink jet method, a. The sparse The hydration to method of manufacturing an electromechanical transducer according to claim 9, wherein the surface modification of the first metal film by using the thiol compound.

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