JP2012199330A - Production method of electromechanical conversion film, droplet ejection head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of an electromechanical conversion film capable of eliminating variation in the thickness.SOLUTION: The production method of an electromechanical conversion film includes a step for coating an underlying layer with a liquid-repellent functional ink, a step for forming a bank film 5 in the shape of a coffee stain having a bank on the circumference of a region coated with the functional ink by drying the functional ink thus applied, and a step for forming an electromechanical conversion film 7 by repeating the application of a functional ink 6 for electromechanical conversion film different from the functional ink inside of the bank film, and calcination of the functional ink 6 thus applied.

Description

  The present invention relates to an electromechanical conversion film manufacturing method, a droplet discharge head, and an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, a droplet discharge head of an ink jet recording apparatus used as an image recording apparatus or an image forming apparatus such as a printer, a facsimile machine, or a copying apparatus has a nozzle that discharges ink droplets and a pressure chamber (ink flow) that communicates with the nozzles. Path, a pressurized liquid chamber, a pressure chamber, a discharge chamber, a liquid chamber, etc.) and a configuration for pressurizing ink in the pressurizing chamber, and ejecting ink droplets from the nozzles by pressurizing the ink. Yes. As a configuration for pressurizing ink, energy generation is made up of an electro-mechanical conversion element (hereinafter referred to as a piezoelectric element), an electrothermal conversion element such as a heater, or a diaphragm that forms a wall surface of an ink flow path and an electrode facing the diaphragm. Means.

  Here, a configuration of a droplet discharge head using a piezoelectric element is illustrated. FIG. 12 is a cross-sectional view illustrating the configuration of the droplet discharge head 400. As shown in FIG. 12, the droplet discharge head 400 forms a pressure chamber 421 by a nozzle plate 410, a pressure chamber substrate 420 (Si substrate), and a vibration plate 430. A nozzle 411 communicating with the pressure chamber 421 is provided on the nozzle plate 410, and a piezoelectric element 440 is provided on the vibration plate 430 via an adhesion layer 441. The droplet discharge head 400 is configured to discharge ink droplets from the nozzles 411 of the nozzle plate 410 by pressing the pressure chamber 421 by vibrating the vibration plate 430 by the piezoelectric element 440. The ink jet recording apparatus forms an image on a recording medium such as paper by a recording head in which droplet discharge heads 400 corresponding to pixels are arranged at a predetermined interval.

  The piezoelectric element 440, which is the main part of the droplet discharge head 400, is formed by laminating a lower electrode 442, an electro-mechanical conversion film 443, and an upper electrode 444 on an adhesion layer 441 by forming a thin film. The lower electrode 442 and the upper electrode 444 are electrodes that perform electrical input to the electromechanical conversion film 443. The electro-mechanical conversion film 443 converts electrical input from the lower electrode 442 and the upper electrode 444 into mechanical deformation. Specifically, for the electro-mechanical conversion film 443, lead zirconate titanate (PZT) ceramics or the like is used, and since these are mainly composed of a plurality of metal oxides, generally, a metal composite oxide and Called.

  A conventional method of forming the piezoelectric element 440 is as follows. First, various vacuum film formation methods (for example, sputtering method, MO-CVD method (chemical vapor deposition method using a metal organic compound), vacuum deposition method, ion plating method), sol-gel method, and the like on the lower electrode 442, After deposition by a well-known film forming technique such as hydrothermal synthesis method, AD (aerosol deposition) method, coating / thermal decomposition method (MOD), etc., the upper electrode 444 is subsequently formed, and then the upper electrode is formed by photolithography and etching. The patterning 444 is performed, and the electro-mechanical conversion film 443 and the lower electrode 442 are similarly patterned for individualization.

  Dry etching of metal composite oxides, particularly PZT, is not an easy processing material. Si semiconductor devices can be easily etched by RIE (Reactive Ion Etching), but this type of material increases the plasma energy of ionic species, so special RIE using ICP plasma, ECR plasma, and helicon plasma is made. (This increases the cost of the manufacturing apparatus). In addition, the selectivity with the base electrode film cannot be obtained. In particular, the etching rate non-uniformity is fatal in a large area substrate. If a hard-to-etch PZT film is disposed only in a desired portion in advance, the above-described processing step can be omitted, but the attempt has not been made except for a part. As methods for individually generating PZT films, there are a hydrothermal synthesis method, a vacuum deposition method, an AD method, and a sol-gel method.

  Hydrothermal synthesis method: PZT selectively grows on Ti metal. If the Ti electrode is patterned, a PZT film grows only at that portion. In order to obtain a PZT film having a sufficient withstand voltage by this method, a relatively thick film having a film thickness of 5 μm or more is preferable (if the film thickness is less than this, any desired dielectric breakdown is easily caused by electric field application. A thin film cannot be obtained). Further, when an element is formed on a Si substrate, since the hydrothermal synthesis is performed in a strong alkaline aqueous solution, it is essential to protect the Si substrate.

  Vacuum deposition method: A shadow mask is used for the production of organic EL and the light emitting layer is patterned, but the PZT film is performed at a substrate temperature of 500 to 600 ° C. This is because the complex oxide needs to be crystallized for the appearance of piezoelectricity, and the substrate temperature is essential to obtain the crystallized film. A general shadow mask is made of stainless steel, and due to the difference in thermal expansion between the Si substrate and the stainless steel, sufficient masking cannot be performed, and a disposable shadow mask has low feasibility. In particular, the MO-CVD method and the sputtering method have a large wraparound phenomenon of the deposited film and are not suitable.

  AD method: A method is known in which a resist pattern is formed in advance by photolithography, and a PZT film is formed in a portion where there is no resist. The AD method is advantageous for a thick film similarly to the hydrothermal synthesis method described above, and is not suitable for a thin film of 5 μm or less. Further, since the PZT film is also deposited on the resist film, a lift-off process is performed after removing a part of the deposited film by the polishing process. Since the uniform polishing process for a large area is complicated and the resist film has no heat resistance, AD film formation is performed at room temperature, and the film is converted into a film exhibiting piezoelectricity through a post-annealing process.

  Sol-gel method: Patent Documents 1 to 3, Non-Patent Documents 1 and 2, etc. introduce examples of coating by an inkjet method. Ink jet ink has a low viscosity, so that it spreads wet on platinum as a substrate. In addition, when a large amount of ink is applied at a time, the edge rises due to the coffee stain phenomenon and the central portion becomes thin, which may be unsuitable for obtaining a thick film. Further, when compared with the vacuum deposition method or the AD method, there may be a variation in film thickness due to a variation in discharge amount between nozzles.

  In the conventional electromechanical conversion film manufacturing method described above, when patterning is performed using the contrast of the lyophobic and lyophilic portions, the unevenness of the contrast immediately becomes the unevenness of the pattern. It was difficult to avoid.

  The present invention has been made in view of the above, and an object of the present invention is to provide a technique that makes it possible to prevent variations in the film thickness of an electromechanical conversion film.

  In order to solve the above-described problems and achieve the object, one aspect of the present invention is a process for applying a functional ink having liquid repellency on a base layer as a base in a method for manufacturing an electromechanical conversion film. And drying the applied functional ink to form a coffee stain-shaped bank film having a bank on the periphery of the area where the functional ink is applied, and inside the bank film, The method includes a step of forming an electromechanical conversion film by repeatedly applying a functional ink for an electromechanical conversion film, which is different from the functional ink, and baking the applied functional ink. .

  According to the present invention, there is an effect that the thickness of the electromechanical conversion film can be made uniform.

FIG. 1-1 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 1-2 is a schematic diagram showing one process of the patterning process of the SAM film. FIG. 1-3 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 1-4 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 2A is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 2B is a schematic diagram illustrating one process of the SAM film patterning process. FIG. 2-3 is a schematic diagram showing one process of the patterning process of the SAM film. FIG. 2-4 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 3A is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 3-2 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 3C is a schematic diagram illustrating one process of the SAM film patterning process. FIG. 3-4 is a schematic diagram illustrating one process of the patterning process of the SAM film. FIG. 4A is a schematic diagram illustrating one process of repeatedly applying a PZT precursor by an inkjet method. FIG. 4B is a schematic diagram illustrating one process of repeatedly applying the PZT precursor by an inkjet method. FIG. 4-3 is a schematic diagram illustrating one process of repeatedly applying the PZT precursor by an inkjet method. FIG. 4-4 is a schematic diagram showing one process of repeatedly applying the PZT precursor by an inkjet method. FIG. 4-5 is a schematic diagram illustrating one process of repeatedly applying the PZT precursor by an inkjet method. FIG. 4-6 is a schematic diagram illustrating one process of repeatedly applying the PZT precursor by an inkjet method. FIG. 5 is a measurement photograph of the water contact angle at the SAM film formation site. FIG. 6 is a measurement photograph of water contact angle at the SAM film removal site. FIG. 7 is a perspective view of the thin film forming apparatus according to the present embodiment. FIG. 8 is a graph showing the PE hysteresis curve of the piezoelectric element created by the thin film formation of this embodiment. FIG. 9 is a cross-sectional view showing a configuration of a droplet discharge head formed by thin film formation according to the present embodiment. FIG. 10 is an explanatory perspective view of the ink jet recording apparatus according to the present embodiment. FIG. 11 is an explanatory side view of the mechanism portion of the ink jet recording apparatus according to the present embodiment. FIG. 12 is a cross-sectional view illustrating the configuration of the droplet discharge head.

  Exemplary embodiments of a method for manufacturing an electromechanical conversion film, a droplet discharge head, and an inkjet recording apparatus will be described below in detail with reference to the accompanying drawings.

  The ink jet recording apparatus has many advantages such as extremely low noise and high-speed printing, and furthermore, an inexpensive plain paper having a degree of freedom of ink can be used. For this reason, the ink jet recording apparatus is widely used as an image recording apparatus or an image forming apparatus such as a printer, a facsimile machine, and a copying apparatus. A droplet discharge head used in an inkjet recording apparatus includes a nozzle that discharges ink droplets and a pressure chamber (an ink channel, a pressurized liquid chamber, a pressure chamber, a discharge chamber, a liquid chamber, etc.) that communicates with the nozzle. And a configuration for pressurizing the ink in the pressurizing chamber, and ejecting ink droplets from the nozzles by pressurizing the ink. As a configuration for pressurizing ink, a piezoelectric type configuration in which ink droplets are ejected by deforming and displacing a diaphragm that forms the wall surface of the pressurization chamber using a piezoelectric element, and a heating resistor disposed in the pressurization chamber There is a bubble type (thermal type) in which bubbles are generated by boiling an ink film using an electrothermal conversion element such as a body to eject ink droplets.

  Further, the piezoelectric type includes a longitudinal vibration type utilizing deformation in the d33 direction, a transverse vibration (bend mode) type utilizing deformation in the d31 direction, and a shear mode type utilizing shear deformation. Recently, a thin film actuator in which a liquid chamber and a piezo element are directly formed on a Si substrate has been devised due to advances in semiconductor processes and MEMS.

  In the following embodiments, a transverse vibration (bend mode) type piezoelectric element utilizing deformation in the d31 direction is taken as an example, and a thin film forming apparatus, a thin film forming method, a piezoelectric element forming method, a droplet discharge head, and an inkjet recording apparatus are provided. explain.

<Formation of piezoelectric layer by sol-gel method>
When the piezoelectric layer is PZT, lead acetate, zirconium alkoxide, and titanium alkoxide compound are used as starting materials (see Non-Patent Document 1) and dissolved in methoxyethanol as a common solvent to obtain a uniform solution. This homogeneous solvent is called a PZT precursor solution.

PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ), and the characteristics differ depending on the ratio. In general, the composition exhibiting excellent piezoelectric characteristics has a ratio of PbZrO ₃ and PbTiO ₃ of 53:47. When expressed by a chemical formula, Pb (Zr0.53, Ti0.47) O ₃ , generally PZT (53/47 ). The starting materials for lead acetate, zirconium alkoxide and titanium alkoxide compounds are weighed according to this chemical formula.

  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.

  Examples of composite oxides other than PZT include barium titanate. In this case, it is also possible to prepare a barium titanate precursor solution by dissolving barium alkoxide and a titanium alkoxide compound in a common solvent. is there.

  When a PZT film is obtained on the entire surface of the underlying substrate, a coating film is formed by a solution coating method such as spin coating, and heat treatments such as solvent drying, thermal decomposition, and crystallization are performed. Since the transformation from the coating film to the crystallized film involves volume shrinkage, it is necessary to adjust the precursor concentration so that a film thickness of 100 nm or less can be obtained in one step in order to obtain a crack-free film.

  When used as a piezoelectric element of a droplet discharge head, the thickness of the PZT film is required to be 1 μm to 2 μm. In order to obtain this film thickness by the above method, the process is repeated ten times.

  In the case of forming a patterned piezoelectric layer by the sol-gel method, the PZT precursor solution in which the wettability of the base substrate is controlled is separately applied.

(Phenomenon of self-arrangement on a specific metal of alkanethiol shown in Non-Patent Document 2)
-Thiol forms SAM film on platinum group metal.
-Pt is used for the lower electrode, and the entire surface thereof is subjected to SAM treatment.
-Since the alkyl group is arranged on the SAM film, it becomes hydrophobic.
Pattern this SAM film by well-known photolithography etching.
Since the patterned SAM film remains even after the resist is peeled off, this part is hydrophobic.
-Since the SAM-removed site is a platinum surface, it is hydrophilic.
-The PZT precursor solution is applied separately using this surface energy contrast.
Depending on the degree of contrast, the PZT precursor solution may be applied separately in a pattern even when applied over the entire surface by spin coating.
-Doctor blade coating may be used.
-Dip coat may also be used.
Ink jet coating may be used to reduce the consumption of the PZT precursor solution.
・ Letter printing is also possible.

  With reference to FIGS. 1-1 to 3-4, three kinds of methods (FIGS. 1-1 to 1-4, FIGS. 2-1 to 2-4, FIGS. 3-1 to 3-4) are used. The process of patterning the SAM film of alkanethiol is shown. It is needless to say that the outermost surface of the substrate 1 that starts patterning shown in FIGS. 1-1, 2-1, and 3-1 is platinum having excellent reactivity with thiol.

Although alkanethiol has different reactivity and hydrophobicity (water repellency) depending on the molecular chain length, it dissolves C ₆ to C ₁₈ molecules in common organic solvents (alcohol, acetone, toluene, etc.) (concentration of several mol / l). ). After immersing the substrate 1 in this solution and taking it out after a predetermined time, the SAM film 2 can be formed on the platinum surface by replacing and washing excess molecules with a solvent and drying (FIGS. 1-2 and 3-2). .

  1-1 to 1-4, a photoresist 3 is patterned by photolithography (FIGS. 1-3), and the SAM film 2 not masked by the photoresist 3 is removed by dry etching. The used photoresist 3 is removed to finish patterning of the SAM film 2 (FIGS. 1-4).

  In the method of FIGS. 2-1 to 2-4, a photoresist 3 is formed first (FIG. 2-2), and then SAM treatment is performed. In the state after the SAM treatment, the SAM film 2 is not formed on the photoresist 3 (FIGS. 2-3). Next, the photoresist 3 is removed to finish the patterning of the SAM film 2 (FIGS. 2-4).

  In the method of FIGS. 3-1 to 3-4, first, the SAM film 2 is formed through the same process as the method illustrated in FIGS. 1-1 to 1-4 (FIG. 3-2). Next, ultraviolet light is irradiated through the photomask 4 to perform exposure (FIG. 3-3). By this exposure, the SAM film 2 remains in the unexposed portion and the exposed SAM film 2 disappears (FIG. 3-4).

  Next, the PZT precursor is repeatedly applied by an inkjet method using the IJ head 208 (see FIG. 7) to form a thin film (FIGS. 4-1 to 4-6). As shown in FIG. 4A, the surface of the SAM film 2 is a hydrophobic portion, and the surface of the substrate 1 not covered with the SAM film 2 is a hydrophilic portion.

  First, the ink droplet 6 is ejected from the IJ head 208 by the ink jet method to form the bank film 5 (FIG. 4-2). Next, heat treatment is performed according to a normal sol-gel process. The heat treatment temperature of the precursor is such that the SAM film 2 disappears and the bank film 5 is baked (FIG. 4-3) due to high temperature treatment such as organic combustion temperature: 500 ° C. and PZT crystallization temperature: 700 ° C.

The second and subsequent steps can be simplified for the following reasons (see FIGS. 4-4 to 4-6).
The SAM film 2 cannot be formed on the oxide thin film. Therefore, after the first treatment, the SAM film 2 is formed only on the exposed substrate 1 without the bank film 5.
In the present embodiment, this self-organization phenomenon is used. The patterning of the conventional SAM film 2 and the patterning of the functional color material (color filter, polymer organic EL, nanometal wiring) using the SAM film 2 are completed by one SAM treatment and the subsequent arrangement of the functional color material. However, in the sol-gel method, the film thickness that can be formed at a time is small, so it is necessary to repeat the process multiple times. Each time, the process of forming a patterned SAM film by photolithography and etching becomes complicated. This embodiment can be realized for the first time by a combination in which an oxide thin film in which a SAM film cannot be formed and a lower electrode as a piezoelectric element are constituent elements and a SAM film can be formed on the lower electrode.
-After the SAM treatment is performed on the first patterned substrate 1 (FIG. 4-4), the PZT precursor solution is separately applied (FIG. 4-5) and heat-treated (FIG. 4-6). Thus, the PZT film 7 is formed.
Repeat this process until the desired film thickness is achieved.
-Patterning by this method can form ceramics to a thickness of 5 μm.

  As a material used for the lower electrode, a metal that is heat resistant and forms a SAM film by reaction with alkanethiol is selected. Copper or silver forms a SAM film but cannot be used because it is altered by heat treatment at 500 ° C. or higher in the atmosphere. Further, although gold satisfies both conditions, it cannot be used because it adversely affects the crystallization of the PZT film 7 to be laminated. An alloy material of platinum, rhodium, ruthenium, iridium, or any other platinum group element mainly composed of platinum such as platinum-rhodium is also effective.

  The vibration plate disposed on the silicon substrate may be a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a film in which these films are laminated with a thickness of several microns. Further, a ceramic film such as an aluminum oxide film or a zirconia film in consideration of a difference in thermal expansion may be used. These materials are insulators.

  Since the lower electrode is electrically connected as a common electrode for inputting a signal to the piezoelectric element, the diaphragm underneath is used as an insulator or an insulator if it is a conductor.

  As the silicon-based insulating film, a thermal oxide film or a CVD deposited film can be used, and the metal oxide film can be formed by a sputtering method.

  When the platinum group lower electrode is disposed on these diaphragms, an adhesion layer for enhancing the film adhesion is required (see FIG. 12). Effective materials for the adhesion layer are titanium, tantalum, titanium oxide, tantalum oxide, titanium nitride, tantalum nitride, and laminated films thereof.

Hereinafter, the details of the method for forming the electromechanical conversion element film by the sol-gel method will be described. FIGS. 1-1 to 1-4 illustrate the process of surface modification of the substrate 1. A platinum electrode (not shown) is formed on the surface of the substrate 1 of FIG. 1-1 by sputtering. FIG. 1-2 shows a state where the SAM film 2 is formed on the entire surface of the substrate 1. The SAM film 2 can be obtained by dipping the substrate 1 in an alkanethiol solution to cause self-alignment. _Here, using CH _{3 (CH} 2) -SH.

  FIG. 1-3 shows a state in which the photoresist 3 is patterned by photolithography in order to protect the necessary SAM film 2 when the SAM film 2 for forming the PZT precursor is removed. In the state shown in FIG. 1C, for example, the surface of the substrate 1 is irradiated with oxygen plasma to remove the portion of the SAM film 2 where the PZT precursor is to be formed. 1-4 shows a state in which the photoresist 3 is peeled off after removing the SAM film 2 in a portion where the PZT precursor is to be formed.

  As shown in FIG. 5, the contact angle of the SAM film 2 formed by this process with respect to pure water is 92 degrees, indicating hydrophobicity. As shown in FIG. 6, the contact angle between Pt and pure water on the substrate 2 from which the SAM film 2 has been removed is 5 degrees, indicating hydrophilicity. In the present embodiment, the example in which the SAM film 2 is removed by oxygen plasma has been described. However, UV (ultraviolet) light irradiation may be used.

  Next, FIGS. 4-1 to 4-6 illustrate a process of applying the PZT precursor to the hydrophilic portion on the substrate 1 formed in the process of FIGS. 1-1 to 1-4 by the inkjet method. . As shown in FIG. 4B, a PZT precursor is obtained from the IJ head 208 of the thin film forming apparatus 20 (see FIG. 7) that forms a thin film by the inkjet method on the hydrophilic region patterned in FIG. 1-4 (FIG. 4A). Apply the solution.

  FIG. 7 is a perspective view of the thin film forming apparatus 20 according to the present embodiment. As shown in FIG. 7, in the thin film forming apparatus 20, Y-axis driving means 201 is installed on the gantry 200. The stage 203 on which the substrate 202 is mounted is driven in the Y-Y ′ direction by the Y-axis driving unit 201. The stage 203 includes suction means (not shown) for fixing the substrate 202 to the stage 203 by vacuum or static electricity. The substrate 202 is fixed on the stage 203 by this suction means. Note that in order to irradiate the back surface of the substrate 202 with laser light (details will be described later), the stage 203 is configured to support the substrate 202 by fitting the substrate 202 into the opening.

  Further, an X-axis support member 204 is installed on the gantry 200 so as to straddle the stage 203 driven in the Y-Y ′ direction by the Y-axis drive means 201. An X-axis drive unit 205 is attached to the X-axis support member 204. A head space 206 mounted on the Z-axis drive unit 211 is attached to the X-axis drive unit 205. Therefore, the head space 206 is driven on the stage 203 in the X-X ′ direction and the Z-Z ′ direction. In the head space 206, an IJ head 208 (IJ: ink jet) for ejecting ink droplets onto a substrate 202 fixed to the stage 203, and an alignment camera 215 are mounted. An ink supply pipe 210 is connected to the IJ head 208. Functional material ink (such as a PZT precursor solution) is supplied to the IJ head 208 from an ink tank (not shown) via an ink supply pipe 210. As a result, the IJ head 208 causes ink droplets such as a PZT precursor solution to be ejected onto the surface of the substrate 202 placed on the stage 203. A head cleaning mechanism 212 for cleaning the IJ head 208 is installed on the gantry 200.

  The alignment camera 215 is a digital camera such as a CCD image sensor or a CMOS image sensor, and a CPU (Central Processing Unit) that controls driving of the Y-axis driving unit 201, the X-axis driving unit 205, the Z-axis driving unit 211, and the like. Connected to the control device. In the thin film forming apparatus 20, the surface of the substrate 202 placed on the stage 203 is imaged by the alignment camera 215, and the control device controls driving based on the captured image, whereby the IJ head 208 with respect to the surface of the substrate 202. Perform alignment. In addition, the laser beam irradiated on the back surface of the substrate 202 is imaged, and the control device controls driving based on the captured image, whereby the ink droplets ejected onto the substrate 202 by the laser beam and the IJ head 208. And alignment. The alignment camera 215 may include a plurality of cameras. In other words, the camera for performing the alignment of the IJ head 208 and the alignment of the laser beam and the ink droplet may be separated. For example, an alignment camera 215 for imaging a laser beam may be installed on the stage 203 side, and imaging from the back side of the substrate 202 may be performed. In the configuration in which the alignment camera 215 is installed on the top of the substrate 202, the laser light is irradiated on the back surface of the substrate 202, and therefore alignment is performed by heat detection using an infrared camera or the like.

  On the opposite side of the head space 206 in the Y-Y ′ direction, a laser Z-axis driving unit 214 that includes a laser head 213 and is driven in conjunction with the Z-axis driving unit 211 is disposed. The laser Z-axis driving unit 214 is attached to the X-axis driving unit 205 and shares movement in the X-X ′ direction with the head space 206. Accordingly, the head space 206 and the laser head 213 are synchronized in movement in the Y-Y ′ direction and the X-X ′ direction with respect to the substrate 202 placed on the stage 203. A reflector 216 is installed on the gantry 200 directly below the laser head 213 driven in the X-X ′ direction. The reflection plate 216 reflects the laser light emitted from the laser head 213 and guides it to just below the substrate 202.

  PZT (53/47) is formed as a piezoelectric layer by the thin film forming apparatus 20 described above. In the synthesis of the precursor coating solution, lead acetate trihydrate, isopropoxide titanium, and isopropoxide zirconium were used as starting materials. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. The lead amount is 10 mol% excess 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 / l.

  The film thickness obtained by a single sol-gel film formation is preferably 100 nm, and the precursor concentration is optimized from the relationship between the film formation area and the amount of applied precursor (thus not limited to 0.1 mol / l). . A bank forming solution having the same composition of the PZT precursor solution but different solvents was also synthesized. The bank forming solution is further added with a solvent having a surface tension and a viscosity forming a height necessary for forming the bank. The solvent to be added differs depending on the height of the bank. Specifically, the solvent to be added is selected so as to be substantially the same as the film thickness of the electromechanical conversion film that forms the height of the bank. Thus, by making the height of the bank substantially the same as the film thickness of the electromechanical conversion film, liquid leakage during film formation can be avoided and the highest position of the bank can be prevented from protruding. . The film thickness of the bank film 5 except for the bank may be thinner than the bank thickness, or the base layer may be exposed in the area excluding the bank. Thus, by reducing the film thickness except for the bank portion, the influence of the bank material (contact failure) on the underlying electrode contact can be reduced.

  This bank forming solution was applied onto the patterned SAM film by the ink jet method (see FIG. 4-2). By discharging only the hydrophilic portion without discharging droplets on the SAM film by the ink jet method, a coating film was formed only on the hydrophilic portion due to the contact angle contrast. In addition, the coating film causes a coffee stain phenomenon due to the surface energy difference between the liquid repellent and the lyophilic liquid, and a bank is formed. The bank film 5 having this bank is subjected to drying, organic matter decomposition, and crystallization treatment to obtain the state shown in FIG. Thereafter, as shown in FIG. 4-4, a PZT precursor liquid is dropped into the bank film 5 by an ink jet method, followed by drying and organic substance decomposition, whereby a PZT film 7 is obtained. As a result, no cracks or the like occurred in the PZT film 7. As described above, the PZT precursor only needs to be dropped inside the bank, so in this embodiment, pattern collapse caused by contrast unevenness can be greatly reduced, and the electromechanical conversion film to be formed is formed. Variations in thickness can be taken into account. Further, since the liquid repellent treatment can be omitted, the time can be significantly reduced.

  The coating process in the bank film 5 illustrated in FIG. 4-3 was repeated 6 times to obtain a 540 nm PZT film 7, and then crystallization heat treatment (temperature 700 ° C.) was performed by RTA (rapid heat treatment). As a result, no defects such as cracks occurred in the PZT film 7. Further, the application of PZT precursor into the bank film 5 → drying → decomposition of organic substances was repeated 6 times for crystallization treatment. As a result, no defects such as cracks occurred in the PZT film 7, and the film thickness reached 1000 nm.

An upper electrode (platinum) was formed on the patterned film, and electrical characteristics and electro-mechanical conversion ability (piezoelectric constant) were evaluated. FIG. 8 is a graph showing the PE hysteresis curve of the piezoelectric element created by the thin film formation of this embodiment. The relative dielectric constant of the film is 1220, the dielectric loss is 0.02, the remanent polarization is 19.3 uC / cm ² , the coercive electric field is 36.5 kV / cm, and it has the same characteristics as a normal ceramic sintered body. all right.

  The electromechanical conversion ability was calculated from the amount of deformation by applying an electric field measured with a laser Doppler vibrometer and adjusted by simulation. The piezoelectric constant d31 was −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.

  Note that the bank forming solution is not PZT but PT (titanate) or PZ (lead zirconate), that is, the bank forming solution contains a part of the components used for PZT, and Pb, Zr By including any one of Ti and Ti, it is possible to suppress composition variation due to a difference in decomposition rate that occurs in a high-temperature process such as organic matter decomposition or crystallization, and it is possible to suppress a decrease in pressure resistance due to composition shift. Further, by performing the crystallization process with a laser, damage (accumulation of thermal stress and diffusion of the horny layer of the substrate 1) due to heat outside the pattern can be reduced.

  FIG. 9 is a cross-sectional view showing a configuration of a droplet discharge head 40 formed by thin film formation according to the present embodiment. As shown in FIG. 9, the droplet discharge heads 40 are formed side by side at a predetermined interval, assuming that one droplet discharges an ink droplet for one pixel. In the present embodiment, the piezoelectric element 440 in the drawing can be formed by a simple manufacturing process (and having performance equivalent to that of bulk ceramics), and the subsequent etching removal from the back surface for the pressure chamber 421, a nozzle having a nozzle 411 The droplet discharge head 40 can be formed by bonding the plate 410. In FIG. 9, descriptions of supply means, flow paths, and fluid resistance for supplying ink liquid to the pressure chamber 421 are omitted.

  Next, an example of an ink jet recording apparatus equipped with the above-described droplet discharge head 40 will be described with reference to FIGS. FIG. 10 is an explanatory perspective view of the ink jet recording apparatus according to the present embodiment. FIG. 11 is an explanatory side view of the mechanism portion of the ink jet recording apparatus according to the present embodiment.

  As shown in FIGS. 10 and 11, an ink jet recording apparatus 50 is mounted on a carriage 93 that can move in the main scanning direction inside a recording apparatus main body 81, and a droplet discharge head formed by the above-described thin film formation. The recording mechanism 94 and the like, and the printing mechanism portion 82 including the ink cartridge 95 that supplies ink to the recording head 94 are accommodated. A sheet feeding cassette 84 (or a sheet feeding tray) on which a large number of sheets 83 can be stacked from the front side can be removably attached to the lower part of the recording apparatus main body 81, and the sheets 83 can be manually inserted. The manual feed tray 85 for feeding paper can be turned over, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, a required image is recorded by the printing mechanism unit 82, and then the rear side is placed. Paper is discharged to the attached paper discharge tray 86.

  The printing mechanism 82 holds a carriage 93 slidably in the main scanning direction by a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk) ink droplets are ejected from a recording head 94 including the droplet ejection head formed by the above-described thin film formation. (Nozzles) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 95 for supplying ink of each color to the recording head 94 is replaceably mounted on the carriage 93.

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

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

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

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

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

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

  When a discharge failure occurs, the discharge port (nozzle) of the recording head 94 is sealed by the capping unit, and bubbles and the like are sucked out together with the ink from the discharge port by the suction unit through the tube. Etc. are removed by the cleaning means, and the ejection failure is recovered. 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.

  In the ink jet recording apparatus 50 described above, since the recording head 94 using the droplet discharge head formed by the above-described thin film formation is mounted, there is no ink droplet discharge failure due to vibration plate drive failure and stable ink droplet discharge. Characteristics are obtained and image quality is improved.

DESCRIPTION OF SYMBOLS 1 Substrate 2 SAM film 5 Bank film 6 Ink droplet 7 PZT film 20 Thin film forming apparatus 40 Droplet discharge head 50 Inkjet recording apparatus 94 Recording head 200 Yard driving means 202 Substrate 203 Stage 204 X-axis support member 205 X-axis driving Means 206 Head space 208 IJ head 211 Z-axis drive means 213 Laser head 215 Alignment camera 216 Reflector 400 Droplet ejection head 440 Piezoelectric element

JP 2010-16280 A JP 2008-251203 A JP 2010-82562 A

K. D. Budd, S. K. Dey, D. A. Payne, Proc. Brit. Ceram. Soc. 36, 107 (1985) A. Kumar and G. M. Whitesides, Appl. Phys. Lett., 63, 2002 (1993)

Claims (9)

A step of applying a functional ink having liquid repellency on a base layer as a base;
Drying the applied functional ink to form a coffee stain-shaped bank film having a bank on the periphery of the area where the functional ink is applied; and
A step of forming an electromechanical conversion film by repeatedly applying a functional ink for an electromechanical conversion film different from the functional ink and firing the applied functional ink inside the bank film. When,
A method for producing an electromechanical conversion film comprising: The film thickness of the bank film excluding the bank is thinner than the bank, or the region has the underlying layer exposed.
The method for producing an electromechanical conversion film according to claim 1. The thickness of the bank is substantially the same as the thickness of the electromechanical conversion film;
The method for producing an electromechanical conversion film according to claim 1 or 2. The electromechanical conversion functional ink contains at least one of Pb, Zr, and Ti;
The method for producing an electromechanical conversion film according to any one of claims 1 to 3. The functional ink for forming the bank film includes a part of the components used in the functional ink for electromechanical conversion.
The method for producing an electromechanical conversion film according to claim 1, wherein: The method for producing an electromechanical conversion film according to claim 1, wherein the functional ink is dropped using an inkjet method. Using a laser for firing the applied functional ink;
The method for producing an electromechanical conversion film according to any one of claims 1 to 6.   A droplet discharge head using a piezoelectric element formed by the method for manufacturing an electromechanical conversion film according to claim 1.   An ink jet recording apparatus comprising the droplet discharge head according to claim 8.

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