JP2013016724A - Pattern forming substrate, method for manufacturing piezoelectric actuator, piezoelectric actuator, droplet discharge head and droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming substrate capable of allowing a film having a fine pattern to be precisely formed with a desired film thickness by repeating a step of performing heat treatment while a fluid is attached, and a method for manufacturing a piezoelectric actuator using the pattern forming substrate.SOLUTION: In a pattern forming substrate 10 for forming a film patterned by performing heat treatment while a predetermined fluid is attached to a specified region, surface modification through which the specified region has affinity with the fluid and a region other than the specified region has not affinity with the fluid is performed. A metal film as a processing object of the surface modification of the pattern forming substrate 10 is formed by laminating a Pt film 53, and an MOC film 52 comprising at least one metal element selected among Ti, Ta, Zr, V, Nb, Mo and W, an oxygen element and a carbon element is used as a base substance.

Description

  The present invention relates to a pattern forming substrate, a piezoelectric actuator using the pattern forming substrate and a manufacturing method thereof, a droplet discharge head including the piezoelectric actuator, and a droplet discharge apparatus including the droplet discharge head. Is.

  In general, a printer, a fax machine, a copier, a plotter, or an image forming apparatus that combines these functions includes, for example, a droplet ejection head that ejects ink droplets, and ink droplets are applied to a sheet while transporting a medium. There is an ink jet recording apparatus that forms an image by adhering. The medium here is also referred to as “paper”, but the material is not limited, and a recording medium, a recording medium, a transfer material, a recording paper, and the like are also used synonymously. The image forming apparatus means an apparatus for forming an image by ejecting liquid droplets on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramic. The image formation is not only giving an image having a meaning such as a character or a figure to the medium but also giving an image having no meaning such as a pattern to the medium (simply ejecting a droplet). Also means. The ink is not limited to so-called ink, and is not particularly limited as long as it becomes liquid when ejected. For example, the ink is a generic term for liquids including DNA samples, resists, pattern materials, and the like. Use.

  In recent years, inkjet heads used as piezoelectric actuators in the above-described inkjet recording apparatus have accelerated the flow toward higher density, and a piezoelectric element formed on a diaphragm by laminating thin films from a conventional system using laminated piezoelectric elements. The method to be used (Patent Document 1) is being transferred. In the latter method, a diaphragm made of an insulator is formed on a flow path forming substrate (Si substrate) that forms an ink liquid chamber, and a piezoelectric element made of a piezoelectric film sandwiched between electrodes is arranged on the diaphragm. It becomes composition. As the piezoelectric film, lead zirconate titanate (PZT) ceramics or the like is used. An electrode adhesion layer is provided between the diaphragm and the electrode (lower side). In this ink jet head, a voltage is applied to the electrode, and the deformation of the piezoelectric film according to the voltage is transmitted to the ink in the ink liquid chamber via the vibration plate, and the compressed ink in the ink chamber is transferred to the nozzle plate. It is discharged from the nozzle hole formed in the.

As a method for producing a piezoelectric film with a fine pattern corresponding to high density, a piezoelectric precursor solution charged with a desired composition on an electrode serving as a substrate is coated in a fine pattern by an inkjet method (inkjet coating). It is known to form a piezoelectric film by forming a coating film and solidifying and crystallizing the coating film of this piezoelectric precursor solution by heat treatment. The method using inkjet coating is considered promising from the viewpoint of the environment because of the ease of forming the apparatus, the ease of pattern formation, and the small amount of solution that is wasted. Moreover, as heat processing temperature of the coating film of a piezoelectric precursor solution, 350-550 degreeC is required for solidification, and 650-800 degreeC is required for crystallization. For this reason, the electrode material to which the piezoelectric precursor solution is applied needs heat resistance and heat diffusibility. As specific materials for electrodes having such thermal characteristics, refractory noble metal materials centering on the Pt group and IrO ₂ , SrRuO ₃ , and LaNiO _{3 that} are conductive oxide materials are known (Patent Literature). 2-4).

  Further, in order for the piezoelectric film of the piezoelectric element to exhibit desired piezoelectric characteristics, it is necessary to form the piezoelectric film in a desired film thickness. However, since thermal shrinkage is accompanied by crystallization, it is preferable to obtain a film thickness of 100 nm or less in a single step in order to obtain a crack-free film. For this reason, in order to obtain a desired film thickness, a piezoelectric film forming process including ink jet coating and heat treatment is repeated.

  On the other hand, as a technology for precisely producing a thin film with a fine pattern, surface treatment is performed on the substrate to form an affinity region and a non-affinity region for the solution, and the affinity region is utilized using affinity contrast. There is known a method of selectively applying a solution only to a resin. As surface treatment technology for forming solution affinity and non-affinity regions in a pattern on a substrate, surface modification is performed using a self-assembled monolayer film or a surface treatment film called a SAM (Self-Assembled Monolayer) film. The method of performing is known (for example, patent document 5).

  For example, when a metal such as Pt is immersed in a thiol compound solution, the thiol compound self-aligns on the metal surface to form a SAM film. After immersing the Pt substrate in a thiol compound solution to form a SAM film on the entire surface, the SAM film is patterned by photolithography edging, and a region where the SAM film is formed on the substrate and a region where the substrate is exposed Is formed. Moreover, a SAM film can be formed only on the surface of a Pt metal film by immersing a substrate made of a conductive oxide or the like in which a Pt metal film is laminated in a pattern in a thiol compound solution. In any method, depending on the type of thiol compound, the region where the SAM film is formed is surface-modified so as to show either affinity or non-affinity for the solution compared to the region where the substrate is exposed. Is done. When the precursor solution is applied to the substrate whose surface has been modified in a pattern by such a method, the precursor solution is applied only to the affinity region without spreading to the non-affinity region. For this reason, a thin film having a fine pattern as patterned can be precisely produced by forming the SAM film in a fine pattern.

  In order to produce a piezoelectric film of a piezoelectric element in a precise fine pattern, a piezoelectric film forming process comprising the above-described surface modification of the substrate by SAM film formation, inkjet coating of a piezoelectric precursor solution, and heat treatment Is repeated until the piezoelectric film is laminated to a desired film thickness. Note that since the SAM film is decomposed by heat treatment, it is necessary to form the SAM film for each step. In addition, as the substrate (piezoelectric element electrode) on which the piezoelectric film is formed, a Pt substrate, which is a high melting point noble metal material, or a substrate in which a Pt film is laminated in a pattern shape using a conductive oxide material as a substrate can be used. However, when the above piezoelectric film forming process is repeated using such a substrate, the piezoelectric precursor solution protrudes into the non-affinity region during inkjet coating despite the surface modification by the SAM film. Occurred.

  This is because when the high-temperature heat treatment necessary for crystallization is repeated, the lower layer component gradually diffuses from the lower electrode adhesion layer through the substrate, and finally the lower layer component appears on the Pt surface on which the SAM film is formed. End up. As a result, the surface energy of the Pt surface that forms the SAM film changes, making it difficult to form the SAM film. That is, if the piezoelectric film forming process is repeated until a desired film thickness is obtained, the surface modification by the SAM film cannot be performed satisfactorily, and the affinity contrast is lowered. In a substrate having a low affinity contrast, the piezoelectric precursor solution protrudes into a non-affinity region that is outside the pattern during inkjet coating. For this reason, it becomes difficult to produce a piezoelectric film having a precise fine pattern. Such diffusion of the lower layer component due to repeated heat treatment occurs remarkably in a substrate using a refractory noble metal material.

  As mentioned above, although the subject of this invention was demonstrated using the piezoelectric material film of the piezoelectric element of the piezoelectric actuator for inkjet, it is not restricted to this. The same problem occurs in the piezoelectric element of the ferroelectric memory using the same material system and the same electrode configuration as the piezoelectric element of the inkjet head.

  Furthermore, not only piezoelectric elements, but repeatedly applying a surface treatment in the form of a pattern to an electrode serving as a substrate, a fluid having a desired component is adhered thereon to form a coating film, and heat treatment is applied. The same problem occurs with respect to an element that forms a thin film with a fine pattern by solidification and crystallization.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to precisely produce a fine pattern film with a desired film thickness by repeatedly performing a heat treatment process by attaching a fluid. By providing a pattern forming substrate, a piezoelectric actuator using the pattern forming substrate and a manufacturing method thereof, a droplet discharge head including the piezoelectric actuator, and a droplet discharge apparatus including the droplet discharge head. is there.

  In order to achieve the above object, the invention of claim 1 is a pattern forming substrate for forming a patterned film by attaching a predetermined fluid to a specific region and performing a heat treatment, In order to perform the surface modification so that the specific region has affinity for the fluid and the region other than the specific region has no affinity, one of the two regions is subjected to surface modification treatment. A substrate for pattern formation comprising a substrate having a metal film laminated thereon, the substrate comprising at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element It is characterized by.

  According to the present invention, the substrate of the pattern forming substrate is composed of at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element. Specifically, the metal oxide and carbide are mixed. The metal has a higher melting point and exhibits excellent thermal stability in the order of a simple metal, its oxide, and its carbide. In general, a substance having excellent thermal stability is also excellent in chemical stability and has little interaction with other substances. For this reason, when the metal carbide having a high melting point is used, even if the heat treatment step is repeated, the inflow / diffusion of the lower layer component into the substrate can be suppressed, and it can be prevented from appearing on the surface of the laminated metal film. it is conceivable that. However, the carbide alone has poor adhesion, and the formed film or metal film is easily peeled off, which is not suitable as a substrate for a pattern forming substrate. By using a substrate in which the above metal oxide and carbide are mixed as in the present invention, as shown in an experiment to be described later, the diffusion of a lower layer component through the substrate is suppressed as compared with a conventionally used substrate. It can suppress appearing on the metal film surface which is the object of modification. For this reason, even if the process of attaching the fluid and performing the heat treatment is repeated, the surface of the metal film can be satisfactorily modified, and the protrusion of the fluid outside the specific region can be suppressed. In addition, the adhesion of the film onto the substrate can be improved. Therefore, according to the pattern forming substrate of the present invention, even when a film is formed by a process of repeating heat treatment, a fine pattern film can be precisely manufactured with a desired film thickness.

  According to the present invention, a pattern forming substrate capable of accurately producing a fine pattern film with a desired film thickness by repeatedly performing a heat treatment process by attaching a fluid, and a piezoelectric element using the pattern forming substrate There is an excellent effect that it is possible to provide an actuator, a manufacturing method thereof, a droplet discharge head including a piezoelectric actuator, and a droplet discharge apparatus including the droplet discharge head.

The perspective view of the substrate for pattern formation of this embodiment. The block diagram in the case of using the pattern formation board | substrate of this embodiment for a piezoelectric actuator. Sectional drawing of the piezoelectric actuator of this embodiment. FIG. 3 is a cross-sectional view of a droplet discharge head according to the present embodiment. Explanatory drawing of the formation process flow of the piezoelectric film of this embodiment. The figure which showed each time of the formation process of the piezoelectric material film of this embodiment. Explanatory drawing of the specific resistance change at the time of changing the quantity of the carbide | carbonized_material in this embodiment. FIG. 3 is an exploded perspective view of a droplet discharge head according to the present embodiment. 1 is a perspective view illustrating an ink jet recording apparatus according to an embodiment. Side view illustrating the ink jet recording apparatus of this embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a pattern forming substrate 10 of the present embodiment. FIG. 2 is a configuration diagram when the pattern forming substrate 10 is used for a piezoelectric actuator.
The pattern forming substrate 10 is finely patterned on a substrate composed of a film 52 composed of at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element. A Pt film 53, which is a metal film, is laminated. Hereinafter, for description, the thin film 52 composed of at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element is referred to as an MOC film 52. The Pt film 53 laminated on the MOC film 52 is laminated in a region other than the specific region where the piezoelectric precursor solution as a fluid is applied, and the MOC film 52 is exposed in the specific region.

  When the piezoelectric actuator is manufactured, as shown in FIG. 2, the Si substrate 30, the diaphragm 40 made of an insulator, the electrode adhesion layer 51, the lower electrode 50 made of a refractory noble metal, and the pattern forming substrate 10 are laminated. Is used. Then, a SAM film is formed on the Pt film 52 of the pattern forming substrate 10 to perform surface modification, and a piezoelectric precursor solution is applied only to a region where the MOC film 52 is exposed, and heat treatment is performed. A film 60 is formed. Then, upper electrodes 70 and 71 are formed on the piezoelectric film 60 to form a piezoelectric actuator as shown in FIG.

  Here, when the heat treatment is repeated to form the piezoelectric layer 60 in a desired film thickness, the components contained in the lower electrode adhesion layer 51 diffuse through the refractory metal film constituting the lower electrode 50, and Pt It appears on the surface of the film 53. Some of these components change the surface energy of the Pt film 53. This change in surface energy makes it difficult to form a SAM film, and the affinity contrast is lowered even when surface modification is performed.

  Therefore, in the present embodiment, a material having high heat resistance and barrier properties on the lower side of the Pt film 53 and capable of ensuring adhesion to both the piezoelectric precursor solution and the Pt film 53. Select and use a film formed of this material. Further, in order to use this film as an electrode of the piezoelectric film 60, a material having a small electric resistance is desired. By providing a film of a material having such characteristics, an affinity contrast to the piezoelectric precursor solution can be stably secured. As such a film, a MOC film 52 composed of at least one metal selected from Ti, Ta, Zr, V, Nb, Mo, and W of the present invention, oxygen, and carbon is used as a Pt film to be surface-treated. It is effective to place it below 53.

Next, material selection for the MOC film 52 will be described.
The inventor of the present application investigated melting points of several simple metals, oxides, carbides and nitrides. The results are shown in Table 1.

  As shown in Table 1, it was found that the carbide has a higher melting point than the oxide and is excellent in thermal stability. It is considered that the excellent thermal stability is chemically stable in many materials, has little interaction with substances, and is effective as a barrier layer. However, the carbide is not necessarily good in adhesion to many substances, for example, as used as a mold material when molding a glass material. TiC or the like used as a metal tool is formed at a high temperature using a special forming method such as ion plating with respect to a metal tool to ensure adhesion. The reason why the film is formed by using such a method is that if it is formed normally, sufficient adhesion cannot be obtained, and film peeling occurs when it is used as a tool.

  Therefore, a mixture of these carbides and oxides was used as a method for improving adhesion. By using a mixture, a barrier layer having chemical stability and adhesion can be obtained. The film thickness of such a metal, oxygen, and carbon film may be thinner than the known adhesion layer film thickness range because of high chemical stability, and is about 2 to 50 nm. Desirably, 2 to 20 nm is suitable. If it is less than 2 nm, it is difficult to uniformly cover the entire surface as a film, and if it exceeds 50 nm, displacement of the piezoelectric film starts to be inhibited. The thickness is preferably 30 nm or less, more preferably 20 nm or less.

Further, the melting points of metal oxide electrodes conventionally used as the substrate of the piezoelectric layer were also examined. The results are shown in Table 2. As Table 2 shows, even when the melting points of these metal oxide electrodes are compared, many carbides have a higher melting point. For this reason, it can be judged that it is chemically stable.

Next, a more detailed description will be given using an embodiment of the droplet discharge head 1 that employs a piezoelectric actuator configured using the pattern forming substrate 10.
FIG. 4 is a cross-sectional view of the droplet discharge head 1 that employs a piezoelectric actuator configured using the pattern forming substrate 10 of the present embodiment.
The droplet discharge head 1 shown in FIG. 4 is supplied to the nozzle holes 21 by laminating a nozzle plate 20 in which the nozzle holes 21 are formed, a flow path forming substrate (Si substrate) 30 and a vibration plate 40. A pressurizing chamber 31 for storing the liquid to be stored is formed. On the vibration plate 40, piezoelectric elements including a lower electrode 50, a pattern forming substrate 10, a piezoelectric layer 60, and upper electrodes 70 and 71 are laminated to constitute a piezoelectric actuator. Further, an electrode adhesion layer 51 is laminated between the vibration plate 40 and the lower electrode 50.

  The droplet discharge head 1 having such a configuration boosts the liquid in the pressurizing chamber 31 by driving a piezoelectric actuator, and pushes out the liquid in a meniscus state that closes the nozzle hole 21 by the pressure from the nozzle hole 21. Let the drops be ejected. When used as a piezoelectric element of such a droplet discharge head 1, the film thickness of the piezoelectric film 60 is required to be 1 μm to 2 μm. However, since the production of the piezoelectric film 60 involves thermal shrinkage during crystallization, it is preferable to obtain a film thickness of 100 nm or less in a single process in order to obtain a crack-free film. For this reason, in order to obtain a desired film thickness, the steps of inkjet coating and heat treatment are repeated ten times or more to produce the piezoelectric film 60.

  Here, the inkjet coating used in the process of manufacturing the piezoelectric actuator will be described. Inkjet coating is drawing by an inkjet method for forming a desired pattern of a fluid. Ink jet coating has been applied and developed for various patterns, including printers, because of the simplicity of the apparatus and the ease of pattern formation. In particular, in the industrial field, studies are being made on use in fields such as wiring pattern formation that has been conventionally performed by photolithography and liquid crystal color filter manufacturing that has been manufactured through a number of processes. Photolithography generally requires many processes such as development, exposure, and etching, while ink jet methods can be used to create ink, and the ink is filled into the ink jet head, and only where necessary. In addition, it is possible to manufacture by simply applying the necessary amount, curing and forming. In addition, since the inkjet method can eject a single droplet from one nozzle when needed, it can easily form an arbitrary pattern, and less waste solution is discarded, which is also promising from an environmental standpoint. Has been.

  A self-assembled monolayer SAM (Self-Assembled Monolayer) film used in the process of manufacturing the piezoelectric actuator will be described. For example, by applying a SAM material that is an organic molecule having a functional group such as a thiol group (SH group) that forms a chemical bond with a metal surface such as gold (Au) or platinum (Pt) as a terminal group. Then, chemical bonds such as gold-sulfur atoms and platinum-sulfur atoms are formed on the metal surface. The anchored organic molecules are ordered and arranged side by side due to the restriction from the metal surface and the interaction between the organic molecules, forming a monolayer. The monomolecular film thus formed is called a SAM film.

  Organic molecules that are physically adsorbed to other parts without chemically bonding to the metal surface are reversible, so the unreacted organic molecules that have been physically adsorbed are removed by a cleaning operation after film formation. As a result, only a monomolecular layer anchored by chemical bonding remains on the surface, and a thin film is formed. Specifically, examples of the SAM material include pentafluorothiol, hexadecanethiol, and perfluorodecanethiol formed by any combination of thiol compounds, disulfide compounds, and isocyanide compounds (see Patent Document 5).

  Next, based on Example 1, manufacture of the pattern formation board | substrate 10 using the MOC film | membrane 52 and its characteristic are demonstrated. Further, the manufacture and characteristics of the piezoelectric actuator in which the piezoelectric film 60 is formed on the pattern forming substrate 10 will be described.

<Example 1>
The pattern forming substrate 10 was produced by the following procedure.
First, the SiO ₂ insulating film was formed by thermally oxidizing the surface of the Si substrate 30 shown in FIG. This SiO ₂ film becomes the diaphragm 40. The SiO ₂ film thickness at this time was 2 μm.

Next, a Ti metal film was formed on the SiO ₂ / Si substrate as an electrode adhesion layer 51 serving as an adhesion layer between the Si substrate 30 and the lower electrode 50. The formation conditions of the electrode adhesion layer 51 are a substrate temperature of 300 ° C., an RF input power of 500 W, an Ar gas pressure of 5 × 10 ⁻³ Torr, and a formed film thickness of 50 nm.

Next, a Pt electrode as the lower electrode 50 was formed with a film thickness of 200 nm. The process conditions were a substrate temperature of 300 ° C., an RF input power of 500 W, and an Ar gas pressure of 3 × 10 ^{−3 to} 5 × 10 ⁻³ Torr. Thereby, the (111) plane of the lower electrode 50 is oriented in the film thickness direction.

Next, a film containing carbon and oxygen containing Ti as a metal component was formed as the MOC film 52 on the lower electrode 50. The formation of the target is the following procedure. Sputtering using 30 mol% TiO ₂ and 70 mol% TiC material powder, uniformly mixing and then sintering into a sputtering target by the HIP method, resulting in a composition of (TiO ₂ ) _0.3 (TiC) _0.7 A target was formed, and an MOC film 52 was formed by sputtering using this target. It is a mixture of oxides and carbides in the target preparation state, and it seems that the state does not change even after sintering.

Next, a Pt film 53 for applying a SAM material was formed. The film thickness is 50 nm, and the film formation conditions are a substrate temperature of 300 ° C., an RF input power of 500 W, and an Ar gas pressure of 3 × 10 ^{−3 to} 5 × 10 ⁻³ Torr. Further, in order to pattern this Pt film 53, after forming a resist pattern as a mask using a photolithographic process, only the Pt film 53 was etched to form a surface pattern as shown in FIG. In this state, the pattern forming substrate 10 in which the Pt film 53, which is a noble metal film, and the MOC film 52 containing carbon and oxygen using Ti as a metal component was formed.

  FIG. 5 is an explanatory diagram of a process flow for forming a piezoelectric film. FIG. 5A shows a state where the MOC film 52 is formed, and FIG. 5B shows a state where the Pt film 53 is formed in a pattern. The piezoelectric film 60 is formed on the pattern forming substrate 10 by repeating SAM film formation, ink jet coating, and heat treatment.

  First, when a piezoelectric precursor solution (piezoelectric ink) lands on a piezoelectric precursor solution (piezoelectric ink) described later, an affinity region (parent ink portion) and a non-affinity region (ink repellent) Part). The forming method is performed by applying a SAM material. In the SAM material centering on thiols, the SAM film 54 in which the SAM material is arranged as a monomolecular layer is formed on the metal surface, but it is not formed in other portions. For this reason, in the pattern forming substrate 10, the SAM film 54 is not formed on the surface of the MOC film 52, but only on the surface of the Pt film 53 (FIG. 5C). The surface of the SAM film 54 becomes non-affinity (ink repellent), and the piezoelectric precursor solution (piezoelectric ink) by ink-jet coating adheres only to the MOC film 52 surface. In this example, perfluorodecanethiol (PFDT) was used as the SAM material. As the SAM material, those formed by any combination of thiol compounds, disulfide compounds or isocyanide compounds can be used. Specifically, pentafluorothiol or hexadecanethiol may be used.

  After the SAM film 54 is formed, a piezoelectric material that is an organic substance is discharged by an ink jet method (FIG. 5D). As the piezoelectric material, a piezoelectric precursor solution of PZT was used. Specifically, lead acetate as the Pb source, tetraisopropyl orthotitanate as the Ti source, tetraisopropyl zirconate as the Zr source, ethylene glycol monomethyl ether as a precursor stability and viscosity modifier for liquid such as precipitation prevention, A PZT precursor solution (PZT ink) in which diethylene glycol monomethyl ether, diethylene glycol dibutyl ether, 1-dodecanol, acetylacetone and the like were mixed was used. As the coating apparatus, an inkjet coating apparatus (model: IJ-DESK-SG-1) manufactured by Genesys Co., Ltd. was used, and the above-described PZT precursor solution (PZT ink) was applied while performing pattern alignment. Here, when the PZT precursor solution (PZT ink) is ejected to the exposed portion of the MOC film 52, which is the pattern portion, the SAM film 54 is not against the PZT precursor solution (PZT ink) protruding from the pattern. By showing affinity (ink repellency), it has the effect of adjusting the shape of the PZT pattern.

  Next, a piezoelectric film 60 made of PZT is formed in the PZT precursor solution without thermal treatment (temperature is 300 to 550 ° C.) and crystallization (temperature is 650 to 800 ° C.) (FIG. 5E )). At this time, since a desired film thickness cannot be formed in a single process, the film forming process including application of the SAM material, application of PZT precursor solution (PZT ink), and thermal decomposition is repeated as many times as necessary (FIG. 5). (F) to (h)). In this example, a 20 μm process was repeated to obtain a 2 μm PZT film. FIG. 6 shows each time of repetition of the process.

  Here, until the PZT piezoelectric film 60 having the desired thickness is obtained, the heat treatment at the maximum temperature of 800 ° C. for 3 minutes is repeated 20 times for the pattern forming substrate 10. Conventionally, when this heat treatment is repeated, the substance diffused from the lower layer such as the electrode adhesion layer 51 appears on the surface of the Pt film 53 on which the SAM film 54 is formed, and the surface energy change of the Pt film 53 is changed. As a result, the SAM film 54 cannot be formed satisfactorily. In the present embodiment, such a problem is suppressed by providing the MOC film 52.

  Experimentally, the pattern forming substrate 10 of Example 1 was evaluated by repeating heat treatment at 800 ° C. for 3 minutes in a pseudo manner 20 times. Further, whether there was a change in the surface energy of the Pt film 53 was evaluated by measuring the contact angle of pure water. The results are shown in Table 3. As a reference for the evaluation numerical value, there is no problem if the contact angle of the SAM-Pt film that can stably apply the SAM material so that the SAM film 54 can be formed is 90 ° or more. If the contact angle is less than 90 °, uneven coating of the SAM material occurs, the SAM film 54 cannot be stably formed, and the PZT precursor solution (PZT ink) may adhere. Usually, when this contact angle is 95 to 113 °, no problem occurs in the process. In the configuration of Example 1, the contact angle after repeating heating at 800 ° C. × 3 minutes 20 times was 100 to 105 °, and it was confirmed that there was no problem as a base for applying the SAM material.

Next, after the piezoelectric film 60 was laminated by 2 μm, an upper electrode composed of the conductive oxide electrode 70 and the Pt electrode 71 was formed, and the device was evaluated as a device.
Specifically, LaNiO ₃ as the conductive oxide electrode 70 was formed on the piezoelectric film 60 with a thickness of 80 nm. The formation conditions are a substrate temperature of 300 ° C., RF input power of 300 W, Ar gas pressure of 4.2 × 10 ⁻³ Torr, and oxygen gas pressure of 8 × 10 ⁻⁴ Torr. The reason for introducing oxygen gas is to reduce oxygen vacancies in the LaNiO ₃ film. Further, the Pt electrode 72 was formed with a film thickness of 100 nm. The process conditions are a substrate temperature of 300 ° C., RF input power of 500 W, and Ar gas pressure of 3 to 5 × 10 ⁻³ Torr. If only the characteristics are to be measured, the lamination of only the Pt electrode 71 is sufficient. Then, after forming a resist pattern using a photolithography technique, etching of the laminated structure and resist ashing were performed in the shape shown in FIG. 3 in a cross-sectional view. The upper electrode 70 in FIG. 3 has a strip shape of 45 μm × 1 mm.

  After forming to the above state, a driving voltage was repeatedly applied under the following conditions for a fatigue test after polarization treatment without forming a passivation film for protecting the element. The upper electrode 71 side was set to a positive potential, and the lower electrode 50 side was set to a negative potential (ground potential).

<< Polarization conditions >>
Applied voltage 40V (Slowly increase the voltage from 0V in 3min, hold for 1min, slowly decrease to 0V in 3min.)
Evaluation after polarization Measured with an initial value of capacitance measured with a rectangular wave of 1 kHz applied voltage of the driving voltage repetition application test between the upper electrode and the lower electrode.

<< Test conditions for repeated application of drive voltage >>
Applied voltage DC 0-30V Square wave (Upper electrode is positive potential)
Application period 100 kHz
Duty 50% (time ratio of positive potential application)

The evaluation during the test was normalized with the initial capacitance value after polarization set to 1, and the same evaluation as the evaluation after polarization was performed at each point for each number of times of application to see the attenuation rate. The point at which the initial value was attenuated by 10% after normalization was taken as the fatigue evaluation point. As a result, it was found that up to 10 ¹² times can be secured with attenuation within the initial value of 10% under the above conditions. That is, good results were confirmed for both the initial characteristics and fatigue characteristics of the device.

  In the device formed in this way, after the formation of the interlayer insulating layer, the formation of the wiring electrode, the formation of the passivation film, etc., the liquid chamber excavation processing on the substrate side, the joining of the nozzle plate, the connection of the drive circuit, the ink supply By mounting the members and the like, the droplet discharge head 1 can be assembled.

Further, the pattern forming substrate 10 using the MOC film 52 will be described based on Examples 2 to 6.
<Example 2>
In the first embodiment, the composition of the sputtering target of the MOC film 52 is changed to (TaO ₂ ) _0.2 (TaC) _0.8 instead of (TiO ₂ ) _0.3 (TiC) _0.7 , and otherwise. In the same manner as in Example 1, the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Example 3>
In the first embodiment, the composition of the sputtering target of the MOC film 52 is changed to (ZrO ₂ ) _0.5 (ZrC) _0.5 instead of (TiO ₂ ) _0.3 (TiC) _0.7 , and otherwise. In the same manner as in Example 1, the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Example 4>
In the first embodiment, the composition of the sputtering target of the MOC film 52 is changed to (VO ₂ ) _0.2 (VC) _0.8 instead of (TiO ₂ ) _0.3 (TiC) _0.7 , and otherwise. In the same manner as in Example 1, the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Example 5>
In Example 1, the composition of the sputtering target of the MOC film 52 is changed to (Nb ₂ O ₅ ) _0.3 (NbC) _0.7 instead of (TiO ₂ ) _0.3 (TiC) _0.7. Except for this, the pattern forming substrate 10 of FIG. 1 was produced in the same manner as in Example 1. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Example 6>
In Example 1 above, the composition of the sputtering target of the MOC film 52 is changed to (MoO ₂ ) _0.05 (MoC) _0.95 instead of (TiO ₂ ) _0.3 (TiC) _0.7 , and otherwise In the same manner as in Example 1, the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

  As shown in Table 3, as in Example 1, in the pattern forming substrates 10 of Examples 2 to 6, the contact angle on the Pt film 53 exceeds 90 °, and it can be seen that the SAM material can be satisfactorily applied. It was. For this reason, it can be said that the favorable SAM film 54 can be stably formed. Furthermore, actually, SAM material application and PZT precursor solution (PZT ink) application were performed, but no protrusion of the PZT precursor solution (PZT ink) to the 53 parts of the Pt film was confirmed.

Next, Comparative Examples 1 to 7 will be described.
<Comparative Example 1>
In the first embodiment, instead of (TiO ₂ ) _0.3 (TiC) _0.7 as the MOC film 52, a laminated film of a Ti film and Pt is formed, and the rest is the same as in the first embodiment. A pattern forming substrate 10 shown in FIG. 1 was produced. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. As an initial value, a contact angle of 105 ° was obtained, but as shown in Table 3, after repeating heat treatment at 800 ° C. for 3 minutes 20 times, the contact angle became 70 to 87 °, which was a SAM material. The contact angle was insufficient for the coating.

<Comparative example 2>
In the first embodiment, instead of (TiO ₂ ) _0.3 (TiC) _0.7 as the MOC film 52, a single TiC film is formed, and other than that, the pattern of FIG. An attempt was made to produce the forming substrate 10. However, in the photolithography process after the formation of the Pt film 53 for forming the SAM film, peeling of the film occurred between the Pt film 53 and the TiC film, and the subsequent process was abandoned.

<Comparative Example 3>
In Example 1 above, instead of (TiO ₂ ) _0.3 (TiC) _0.7 as the MOC film 52, (SiO ₂ ) _0.3 (SiC) _0.7 was formed, and the others were performed. In the same manner as in Example 1, the pattern forming substrate 10 shown in FIG. No peeling occurred in the photolithography process after the formation of the Pt film 53 for forming the SAM film. However, when the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, circular peeling from the Pt film was observed.

<Comparative example 4>
In the first embodiment, instead of (TiO ₂ ) _0.3 (TiC) _0.7 as the MOC film 52, (Cr ₂ O ₃ ) _0.3 (CrC) _0.7 is formed, and the others In the same manner as in Example 1, an attempt was made to produce the pattern forming substrate 10 of FIG. No peeling occurred in the photolithography process after the formation of the Pt film 53 for forming the SAM film. However, when the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, delamination of the film itself was observed due to the stress of the film.

<Comparative Example 5>
In Example 1, instead of the MOC film 52, a LaNIO ₃ film and a film thickness of 100 nm were formed. Otherwise, the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Comparative Example 6>
In Example 1 above, instead of the MOC film 52, an SrRuO ₃ film and a film thickness of 60 nm were formed, and the other processes were performed in the same manner as in Example 1 to produce the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

<Comparative Example 7>
In Example 1 above, an IrO ₂ film and a film thickness of 100 nm were formed in place of the MOC film 52, and the pattern forming substrate 10 of FIG. Then, after the heat treatment at 800 ° C. for 3 minutes was repeated 20 times, the contact angle of pure water as in Example 1 was evaluated. The results are shown in Table 3.

  As shown in Table 3, in the pattern forming substrates 10 of Comparative Examples 5 to 7, the contact angle on the Pt film 53 is less than 90 °, uneven application of the SAM material occurs, and the SAM film 54 is stably formed. Cannot be performed, and the PZT precursor solution (PZT ink) adheres.

Next, the oxygen and carbon contents of the MOC film 52 will be described based on the seventh embodiment.
<Example 7>
In Example 7, the specific resistance of the target according to the mixing ratio was investigated with respect to the composition amounts of the metal carbide and oxide forming the MOC film 52. The results are shown in FIG. It can be seen that the carbide composition amount has an inflection point at 20 mol%, and the effect of mixing the carbide is small even in the specific resistance when the carbide composition amount is less than 20 mol%.

Next, a droplet discharge apparatus equipped with the droplet discharge head 1 using the piezoelectric actuator of the first embodiment will be described based on the eighth embodiment.
<Example 8>
FIG. 8 is an exploded perspective view of the droplet discharge head 1 created using the piezoelectric actuator of the first embodiment. In FIG. 8, the nozzle plate 20, the flow path forming substrate (Si substrate) 30, and the protective substrate 72 are shown from the upper side. In FIG. 8, reference numeral 73 denotes a flexible printed circuit board (FPC), and 74 denotes a piezoelectric element protection space. When this droplet discharge head 1 is mounted on an inkjet recording apparatus as an inkjet head and used, there is no ink droplet discharge failure due to drive failure, stable ink droplet discharge characteristics are obtained, and there is no omission of images. Image quality was obtained.

  Here, an example of an ink jet recording apparatus equipped with the droplet discharge head of FIG. 8 will be described with reference to FIGS. FIG. 9 is a perspective view illustrating an ink jet recording apparatus, and FIG. 10 is a side view illustrating the ink jet recording apparatus. The ink jet recording apparatus is a typical example of the droplet discharge apparatus according to the present invention.

  An ink jet recording apparatus 100 shown in FIG. 1 mainly includes a carriage 101 that can move in the main scanning direction inside the recording apparatus main body, a recording head 104 that includes a droplet discharge head 1 mounted on the carriage 101, and a recording head 104. And a printing mechanism 103 including an ink cartridge 102 for supplying ink to the printer.

  In addition, a sheet feeding cassette 130 on which a large number of sheets P can be stacked can be detachably attached to the lower part of the apparatus body from the front side, and a manual feed tray 105 for manually feeding sheets P is provided. The paper P fed from the paper feed cassette 130 or the manual feed tray 105 is taken in, and a required image is recorded by the printing mechanism unit 103. Then, the paper P is discharged to the paper discharge tray 106 mounted on the rear side. Make paper.

  The print mechanism 103 holds a carriage 101 slidably in the main scanning direction by a main guide rod 107 and a sub guide rod 108 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk) ink droplets of each color are ejected. The ink discharge ports (nozzles) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet discharge direction facing downward.

  In addition, each ink cartridge 102 for supplying ink of each color to the recording head 104 is replaceably mounted on the carriage 101. The ink cartridge 102 has an atmosphere port communicating with the atmosphere at the upper side, a supply port for supplying ink to the recording head 104 at the lower side, and a porous body filled with ink inside. The ink supplied to the recording head 104 by the force is maintained at a slight negative pressure.

  Here, the carriage 101 is slidably fitted to the main guide rod 107 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the secondary guide rod 108 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 101 in the main scanning direction, a timing belt 112 is stretched between a driving pulley 110 and a driven pulley 111 that are rotationally driven by a main scanning motor 109, and the timing belt 112 is attached to the carriage 101. The carriage 101 is reciprocally driven by forward and reverse rotations of the main scanning motor 109.

  On the other hand, in order to convey the paper P set in the paper feed cassette 130 to the lower side of the recording head 104, the paper feed roller 113 and the friction pad 114 for separating and feeding the paper P from the paper feed cassette 130 and the paper P are guided. The guide member 115 to be transported, a transport roller 168 that reverses and transports the fed paper P, a transport roller 117 that is pressed against the peripheral surface of the transport roller 116, and a feed angle of the paper P from the transport roller 116. A tip roller 110 is provided. The transport roller 116 is rotated by a sub-scanning motor 128 through a gear train. A printing receiving member 119 is provided as a paper guide member that guides the paper P fed from the transport roller 116 on the lower side of the recording head 104 corresponding to the movement range of the carriage 101 in the main scanning direction. On the downstream side of the printing receiving member 119 in the paper conveyance direction, a conveyance roller 120 and a spur 123 that are rotationally driven to send the paper P in the paper discharge direction are provided, and paper discharge that further sends the paper P to the paper discharge tray 108 is provided. A roller 121 and a spur 124, and guide members 125 and 126 that form a paper discharge path are disposed.

  At the time of recording, the recording head 104 is driven according to the image signal while moving the carriage 101 to eject ink onto the stopped paper P to record one line, and after the paper P is conveyed by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper P reaches the recording area, the recording operation is terminated and the paper P is discharged.

  Further, a recovery device 127 for recovering defective ejection of the recording head 104 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 101. The recovery device 127 includes a cap unit, a suction unit, and a cleaning unit. The carriage 101 is moved to the recovery device 127 side during printing standby and the recording head 104 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 104 is sealed with a capping unit, air bubbles are sucked out together with ink from the discharge port with a suction unit through the tube, and ink or dust adhering to the discharge port surface is collected. 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 is absorbed and held by an ink absorber inside the waste ink reservoir.

  Thus, since the ink jet recording apparatus 100 includes the recording head 104 which is a liquid droplet ejection head (ink jet head) employing the piezoelectric actuator of Example 1, stable ink droplet ejection characteristics can be obtained. , Improve the image quality.

  Further, after creating a recording head 104 which is a droplet discharge head (inkjet head) employing a piezoelectric actuator manufactured using the pattern forming substrate 10 shown in Examples 2 to 6, similarly, the recording head 104 shown in FIGS. Used in an inkjet recording apparatus. As a result, there was no ink droplet ejection failure due to drive failure, stable ink droplet ejection characteristics were obtained, and good image quality was obtained without image omission.

  Although the present embodiment has been described using the piezoelectric film of the piezoelectric element that is the actuator of the inkjet head, the present invention is not limited to this. The present invention can also be applied to a piezoelectric element of a ferroelectric memory using the same material system and the same electrode configuration as a piezoelectric element of an inkjet head.

  Ferroelectric memory is called FeRAM (Ferroelectric Random Access Memory), and as a non-volatile semiconductor memory, the ferroelectric film has a high polarization reversal time (1 ns or less), so high speed operation similar to DRAM can be expected.

What has been described above is an example, and the present invention has a unique effect for each of the following modes.
(Aspect A)
A pattern forming substrate 10 for forming a film such as a piezoelectric film 60 that is patterned by attaching a fluid such as a piezoelectric precursor solution to a specific region and performing a heat treatment, and flows in the specific region A substrate in which a metal film that is subject to surface modification treatment is laminated on one of two regions in order to perform surface modification so that it has affinity for the body and non-affinity in regions other than a specific region This is a pattern forming substrate 10. As this substrate, an MOC film 52 composed of at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element is used. According to this, as described in the above-described embodiment, it is possible to precisely produce a fine pattern film with a desired film thickness by repeatedly performing a heat treatment process by attaching a fluid.
(Aspect B)
In (Aspect A), a refractory noble metal material such as a Pt film 53 is used as the metal film to be surface-modified. Thereby, as described in the above embodiment, a good surface modification process using the SAM film can be performed, and a good affinity contrast can be obtained.
(Aspect C)
In (Aspect A) or (Aspect B), the ratio of at least one metal carbon material selected from Ti, Ta, Zr, V, Nb, Mo, and W among the materials constituting the MOC film 52 is 20 mol% or more. is there. As a result, as described in Example 7 above, the effect of increasing the thermal stability by mixing metal carbide is greatly obtained.
(Aspect D)
A method of manufacturing a piezoelectric actuator having a structure in which a piezoelectric element composed of a piezoelectric film 60 sandwiched between electrodes is laminated on a diaphragm 40, wherein the piezoelectric film 60 is (Aspect A), (Aspect B) or (Aspect C). ), The step of modifying the surface of the pattern forming substrate 10 in a pattern, the step of applying the piezoelectric film precursor solution to the pattern forming substrate 10 in a pattern, and the coating film using the piezoelectric film precursor solution The piezoelectric film 60 is formed until a desired film thickness is obtained by repeating the heat treatment step. As a result, as described in the first embodiment, it is possible to manufacture a piezoelectric actuator in which the piezoelectric film 60 having a fine pattern is precisely formed with a desired film thickness.
(Aspect E)
In a piezoelectric actuator having a configuration in which a piezoelectric element composed of a piezoelectric film 60 sandwiched between electrodes is laminated on a vibration plate 40, (Aspect A), (Aspect B) or (Aspect C) is used as a substrate on which the piezoelectric film 60 is formed. The pattern forming substrate 10 is used. As a result, as described in the first embodiment, a piezoelectric actuator capable of handling a high density in which the piezoelectric film 60 having a fine pattern is precisely formed with a desired film thickness can be obtained.
(Aspect F)
In the droplet discharge head 1 including a nozzle hole 21 that discharges a droplet, a pressurizing chamber 31 that communicates with the nozzle hole 21, and a discharge driving unit that pressurizes the liquid in the pressurizing chamber 31. A part of the wall is constituted by the diaphragm 40, and the piezoelectric actuator of (Embodiment E) is provided as the ejection driving means. As a result, as described in the eighth embodiment, there is no ink droplet ejection failure and stable ink droplet ejection characteristics can be obtained.
(Aspect G)
In the droplet droplet ejection apparatus as the ink jet recording apparatus that employs the droplet ejection head 1 of (Aspect F), as described in Example 8 above, there is no ink droplet ejection failure and stable ink droplet ejection characteristics. As a result, good image quality was obtained with no missing images.

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 10 Pattern formation board | substrate 20 Nozzle board 21 Nozzle hole 30 Si substrate (flow path formation board | substrate)
31 Pressurizing chamber 40 Diaphragm 50 Lower electrode 51 Electrode adhesion layer 52 MOC film 53 Pt film 54 SAM film 60 Piezoelectric film 70 Conductive oxide electrode 71 Upper electrode 72 Protective substrate 100 Inkjet recording device 101 Carriage 102 Ink cartridge 104 Recording head

JP 2004-349712 A JP 2007-088147 A JP 2001-007299 A JP 2000-208725 A Japanese Patent No. 4100388

Claims (7)

A pattern forming substrate for forming a patterned film by attaching a predetermined fluid to a specific region and performing a heat treatment, wherein the specific region has an affinity for the fluid and the specific region In order to perform surface modification so as to make the region other than the region non-affinity, in the pattern forming substrate composed of the base body in which the metal film to be subjected to the surface modification treatment is laminated on one of the two regions,
A pattern forming substrate, wherein the substrate is composed of at least one metal element selected from Ti, Ta, Zr, V, Nb, Mo, and W, an oxygen element, and a carbon element.   2. The pattern forming substrate according to claim 1, wherein the metal film is made of a refractory noble metal material.   The pattern forming substrate according to claim 1 or 2, wherein a ratio of at least one metal carbonaceous material selected from Ti, Ta, Zr, V, Nb, Mo, and W among the materials constituting the base is 20 mol% or more. A substrate for pattern formation, characterized in that A method of manufacturing a piezoelectric actuator having a structure in which a piezoelectric element made of a piezoelectric film sandwiched between electrodes is laminated on a vibration plate,
The piezoelectric film comprises a step of modifying the surface of the pattern forming substrate according to claims 1 to 3 in a pattern, and a piezoelectric film precursor solution, which is a fluid, is applied in a pattern on the pattern forming substrate. And a step of heat-treating the coating film with the piezoelectric film precursor solution to form the piezoelectric film until a desired film thickness is obtained. A method for manufacturing a piezoelectric actuator.   4. A piezoelectric actuator having a structure in which a piezoelectric element composed of a piezoelectric film sandwiched between electrodes is laminated on a vibration plate, wherein the pattern forming substrate according to claim 1 is used as a substrate on which the piezoelectric film is formed. A piezoelectric actuator.   In a droplet discharge head comprising a nozzle hole for discharging a droplet, a pressurizing chamber that communicates with the nozzle hole, and a discharge driving means that pressurizes the liquid in the pressurizing chamber, one of the walls of the pressurizing chamber is provided. 6. A droplet discharge head comprising: a portion comprising a diaphragm; and the piezoelectric actuator according to claim 5 as the discharge driving means.   A droplet discharge apparatus comprising the droplet discharge head according to claim 6.

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