JP2013055173A - Thin film manufacturing method, electromechanical conversion element, liquid discharge head, and inkjet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film manufacturing method in which, while preventing occurrence of a coffee-stain phenomenon by controlling a contact angle to liquid, a thin film is formed by making the liquid wet-expanded uniformly on a substrate, to provide an electromechanical conversion element equipped with the thin film manufactured by the thin film manufacturing method, to provide a droplet discharge head equipped with the electromechanical conversion element and to provide an inkjet recorder.SOLUTION: A thin film obtained by crystallizing functional ink is formed on a substrate by a thin film manufacturing method. This method includes: a liquid repelling film formation process for forming a liquid repelling film on the substrate; a liquid repelling film removal process for removing a part of the liquid repelling film by one method selected from a laser source, a lamp and plasma to form a desired shaped liquid repelling film removal portion which becomes a quasi-hydrophilic part; and a functional ink application process for applying the functional ink to the liquid repelling film removal portion on the substrate by a sol-gel method.

Description

The present invention relates to an ink jet recording apparatus and a liquid discharge head used as an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, and an MFP (multifunction printer), an electromechanical conversion element used in these, an electromechanical conversion element, etc. The present invention relates to a thin film manufacturing method for manufacturing a thin film.
Further, as described above, the present invention can be directly applied to an ink jet recording apparatus equipped with a droplet discharge device used in the printing field, particularly the digital printing field, and can also be applied to a three-dimensional molding technique using an ink jet technique. It is.

  The configuration of the liquid ejection head includes a nozzle that ejects ink droplets, and a pressure chamber that communicates with the nozzle (also referred to as an ink flow path, a pressurized liquid chamber, a pressure chamber, a discharge chamber, and a liquid chamber). An electromechanical conversion element such as a piezoelectric element that pressurizes ink in the pressurizing chamber, or an electrothermal conversion element such as a heater, or an energy generating means comprising a diaphragm that forms the wall surface of the ink flow path and an electrode facing the diaphragm Is provided. The liquid ejection head ejects ink droplets from the nozzles by pressurizing the ink in the pressurized chamber.

Here, the piezoelectric element is formed by laminating a lower electrode (first electrode), a piezoelectric layer, and an upper electrode (second electrode) disposed on a substrate. (See Figure 1)
Each pressure chamber is provided with an individual piezoelectric element for generating ink discharge pressure.
The piezoelectric element converts electrical input into mechanical deformation, and has a laminated structure in which upper and lower electrode pairs for executing electrical input and a thin film such as a piezoelectric body are sandwiched therebetween. As the piezoelectric body having a thin film structure, lead zirconate titanate (PZT) ceramics or the like is used, and these are generally referred to as a metal composite oxide because they mainly include a plurality of metal oxides.

  Until now, in the thin film formation technology using the ink jet method, the substrate is made lyophilic by dry etching, or the SAM (self-assembled monomolecular film) is formed on the substrate to make it lyophobic. Etc., and wetting control of the substrate was performed. Further, a technique for patterning ink only at a desired position by selectively removing the SAM has been developed. As a method for removing the SAM, a technique using laser irradiation or the like has been studied. Furthermore, it has already been known from research by Kyushu University and Professor Fukai that coffee stains (sometimes called coffee rings) are less likely to occur as the contact angle with the liquid increases.

  However, in the conventional substrate processing, the contact angle to the liquid used is too high because the degree of freedom and precision of contact angle control is too low, so the target area does not spread evenly or the contact angle is low. Therefore, there is a problem in that solid components in the liquid accumulate at the edges during drying and coffee stains are generated.

Here, in Patent Document 1 (Japanese Patent Laid-Open No. 2005-327920), a device having a ferroelectric layer or a piezoelectric layer having an arbitrary planar shape can be formed with higher accuracy, lower cost, and shorter tact time. A manufacturing method and a technology relating to devices such as ferroelectric elements and piezoelectric elements obtained thereby are disclosed. More specifically, Patent Document 1 employs a self-assembled monolayer as a surface modification film in order to form a region having a high affinity and a region having a low affinity on the lower electrode. Techniques using electron beams, beams, and light for quality are disclosed.
However, Patent Document 1 does not pay any attention to the problem that coffee stain is generated by completely removing the self-assembled monolayer, and this problem has not been solved.

  The present invention has been made in view of the above problems, and by controlling a contact angle with respect to a liquid, a thin film production capable of forming a thin film so as to spread uniformly on a substrate while preventing coffee stains is achieved. It is an object of the present invention to provide a method, an electromechanical conversion element including a thin film manufactured by the thin film manufacturing method, a droplet discharge head including the electromechanical conversion element, and an ink jet recording apparatus.

A thin film manufacturing method according to the present invention for solving the above problems is a thin film manufacturing method for forming a thin film obtained by crystallizing functional ink on a substrate, and forming a liquid repellent film on the substrate. A liquid repellent film forming step and a liquid repellent film forming a liquid repellent film removal portion having a desired shape to be a semi-hydrophilic portion by removing a part of the liquid repellent film by any one selected from a laser light source, a lamp and plasma A film removing step; and a functional ink applying step of applying the functional ink to the liquid repellent film removing portion on the substrate by a sol-gel method.
In addition, an electromechanical transducer according to the present invention for solving the above-described problems includes a first electrode, a second electrode facing the first electrode, the first electrode, and the second electrode. An electromechanical conversion element comprising an electromechanical conversion film sandwiched between electrodes, wherein the electromechanical conversion film is manufactured by the above thin film manufacturing method, and the first electrode is the above It is a substrate.
Furthermore, a liquid discharge head according to the present invention for solving the above-described problems is characterized by including the above electromechanical conversion element.
Furthermore, an ink jet recording apparatus according to the present invention for solving the above-described problems is characterized by including the above-described liquid discharge head.

  According to the present invention, by controlling the contact angle with respect to the liquid, a thin film manufacturing method capable of forming a thin film so as to spread uniformly on the substrate while preventing coffee stain, and the thin film manufacturing method are used. In addition, an electromechanical conversion element including a thin film, a droplet discharge head including the electromechanical conversion element, and an ink jet recording apparatus can be provided.

It is a schematic diagram which shows the structure of a liquid discharge head. It is a schematic diagram which shows the patterning process of a SAM film. It is a schematic view showing a step of repeatedly oxide electrode solution (LaNiO ₃ or the like) coated by an inkjet method. It is a figure showing the contact angle on platinum. It is a schematic diagram which shows an inkjet coating apparatus. It is a graph which shows the relationship between a laser power and the contact angle with respect to a pure water. It is a schematic diagram which shows a process when a functional ink is provided when a hydrophilic part is formed. It is a schematic diagram which shows a process when a functional ink is provided when a semi-hydrophilic part is formed. It is a graph which shows the relationship between oxygen plasma processing time and the contact angle with respect to pure water. It is a figure showing the hysteresis curve of the PZT film | membrane obtained by this invention. It is a schematic diagram which shows the structure of the liquid discharge head which has several electromechanical conversion elements. 1 is a perspective view showing a configuration of an ink jet recording apparatus equipped with a liquid discharge head according to the present invention. 1 is a side view illustrating a configuration of an ink jet recording apparatus equipped with a liquid discharge head according to the present invention.

The liquid repellent film forming step according to the present invention is a thin film manufacturing method for forming a thin film obtained by crystallizing functional ink on a substrate, and the liquid repellent film forming step for forming a liquid repellent film on the substrate And a liquid repellent film removing step of removing a part of the liquid repellent film by any one selected from a laser light source, a lamp, and plasma to form a liquid repellent film removal portion having a desired shape to be a semi-hydrophilic portion; A functional ink application step of applying the functional ink to the liquid repellent film removal site on the substrate by a sol-gel method.
Next, the thin film manufacturing method according to the present invention, the electromechanical conversion element, the droplet discharge head and the ink jet recording apparatus provided with the electromechanical conversion element will be described in more detail.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

FIG. 1 is a schematic view showing a configuration of an embodiment of a liquid discharge head according to the present invention.
The present invention is also directed to a liquid discharge head and an image forming apparatus using the liquid discharge head. The image forming apparatus is generally called an ink jet recording apparatus, and the ink jet recording apparatus will be described below.

  Inkjet recording devices have many advantages such as extremely low noise, high-speed printing, and the ability to use plain paper that is free of ink and inexpensive, so that printers, facsimiles, copiers, etc. Widely deployed as an image recording apparatus or an image forming apparatus.

  A droplet discharge device used in an ink jet recording apparatus includes a nozzle that discharges ink droplets, and a liquid chamber (also referred to as a discharge chamber, a pressurized liquid chamber, a pressure chamber, or an ink flow path) that communicates with the nozzle. And pressure generating means for discharging ink in the liquid chamber.

  The pressure generating means as described above may be a piezo type that discharges ink droplets by deforming and displacing a diaphragm that forms the wall surface of the discharge chamber using an electromechanical transducer such as a piezoelectric element, or a discharge 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 heating resistor disposed in the nozzle to eject ink droplets. Further, the piezoelectric type includes a longitudinal vibration type using deformation in the d33 direction, a transverse vibration (bend mode) type using deformation in the d31 direction, and a shear mode type using shear deformation. With the progress of semiconductor processes and MEMS, a thin film actuator in which a liquid chamber and a piezo element are directly formed on a Si substrate has been devised.

The present invention relates to a transverse vibration (bend mode) type electric transducer using deformation in the d31 direction.
The electromechanical conversion element 40 is provided with a pair of lower electrode 42 and upper electrode 44 facing each other, and a piezoelectric layer (electromechanical conversion film) 43 is sandwiched between the pair of lower electrode 42 and upper electrode 44. It has a laminated structure. The electromechanical transducer 40 converts electrical energy applied to the electrodes 42 and 44 into mechanical energy (deformation).

<Piezoelectric layer (electromechanical conversion film) 43>
The piezoelectric layer 43 is made of a complex oxide of metal.
First, formation of the piezoelectric layer by the sol-gel method of the piezoelectric layer 43 will be described.
In the case where the piezoelectric layer is PZT (see the technique relating to the formation of a thin film of a metal composite oxide by a sol-gel method shown in Non-Patent Document 1: KDBudd, SKDey, DA Payne, Proc. Brit. Ceram. Soc. 36, 107 (1985) )), Lead acetate, zirconium alkoxide, and titanium alkoxide compound as starting materials and dissolved in methoxyethanol as a common solvent to obtain a uniform solution. This uniform solution is called a PZT precursor solution (functional ink, ferroelectric precursor ink).

PZT (lead zirconate titanate) is a solid solution of lead zirconate (PbTiO 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 base substrate, it is obtained by forming a coating film by a solution coating method such as spin coating and performing heat treatments such as solvent drying, thermal decomposition, and crystallization. Since 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 liquid ejecting apparatus, the thickness of the PZT film is required to be 1 μm to 2 μm. Therefore, in order to obtain this film thickness by the method described above, the process is repeated ten times.

In the case of forming a patterned piezoelectric layer by the sol-gel method, the PZT precursor liquid in which the wettability of the base substrate is controlled is separately applied.
(A non-patent document 2 shows a phenomenon in which alkanethiol can be formed as a self-assembled monolayer (SAM) on an Au film, and a SAM by a microcontact printing method using this phenomenon. See A. Kumar and GM Whitesides, Appl. Phys. Lett., 63, 2002 (1993), as shown in Non-Patent Document 3. See the technique of removing SAM film by applying alkanethiol, decanethiol, MHDA, etc. on Au substrate to form SAM film and scanning with semiconductor laser: Daniel Rhinow and Norert A Hampp, IEEE Transactions on nanobioscience 5, No. 3 (2006).)

The present invention is characterized in that the SAM film is removed by any one of a laser light source, a lamp, and plasma instead of the known photolithography etching, but in the following, an example by a known photolithography etching (conventional) Ex.) Details of the feature of the present invention in which the SAM film is removed by any one of the laser light source, the lamp and the plasma will be described later in the embodiments.
In the present invention, it is preferable to perform heat treatment of the PZT precursor by laser irradiation or lamp instead of performing heat treatment of the PZT precursor according to a normal sol-gel process. An example of performing the heat treatment (conventional example) will be described. Details of the heat treatment of the PZT precursor by laser irradiation or lamp will be described later in Examples.

Thiol forms a SAM film (liquid repellent film; hydrophobic) on the platinum group metal. Therefore, first, Pt is used for the lower electrode, and SAM treatment is performed on the entire surface of the lower electrode. Since the alkyl group is arranged on the SAM film, it becomes hydrophobic.
Next, the SAM film is patterned by a known photolithography etching. At this time, since the patterned SAM film remains even after the resist is peeled off, this portion is hydrophobic, and the portion from which SAM is removed is hydrophilic because it is a platinum surface.
Then, the PZT precursor liquid is separately applied using this surface energy contrast. At this time, although depending on the degree of contrast, the PZT precursor may be applied separately in a pattern even when applied over the entire surface by spin coating. Further, doctor blade coating, dip coating, or inkjet coating may be used when it is desired to reduce the consumption of the PZT precursor solution. Similarly, letterpress printing may be used.

FIG. 2 shows SAM film patterning methods of alkanethiol by three methods.
Needless to say, the outermost surface of the substrate 1 is described as platinum excellent in reactivity with thiol.
Although alkanethiol has different reactivity and hydrophobicity (water repellency) depending on the molecular chain length, it dissolves C6 to C18 molecules in common organic solvents (alcohol, acetone, toluene, etc.). In this case, the concentration of alkanethiol is preferably diluted to about 2 to 3 mol / l with an organic solvent, but it does not preclude changing the concentration as appropriate according to the desired film thickness, characteristics, etc. .
After the substrate 1 is immersed in this solution and taken out after a predetermined time, the SAM film 2 can be formed on the platinum surface by replacing and cleaning the excess molecules with a solvent and drying (B, B ″ in FIG. 2).
C in FIG. 2 patterns the photoresist 3 by photolithography, removes the SAM film 2 by dry etching, removes the resist used for processing, and finishes patterning of the SAM film 2 (D in FIG. 2). ).
For B ′, the pattern of the photoresist 3 is first formed and SAM processing is performed. In the state after the processing, the SAM film 2 is not formed on the photoresist 3 (C ′ in FIG. 2), and the patterning of the SAM film 2 is completed when the resist is removed.
B ″ is formed through the same process as B described above, and the SAM film 2 remains in the unexposed area and the SAM film 2 disappears in the exposed area by irradiating ultraviolet rays through the photomask 3.
As a result, the SAM film 2 is formed at a desired position on the substrate 1 (D in FIGS. 2 and 3).

Specific examples of these will be described. SAM treatment was performed by using CH ₃ (CH ₂ ) ₆ -SH in alkanethiol and immersing it in a 0.01 mol / l (solvent: isopropyl alcohol) solution. Then, after washing and drying with isopropyl alcohol, the process proceeds to a patterning process.
The hydrophobicity after the SAM treatment was measured by a contact angle, and the contact angle of water on the SAM film was 92.2 °. On the other hand, the water contact angle of the platinum sputtered film before the SAM treatment is 5 ° or less (complete wetting), indicating that the SAM film treatment has been performed.
A photoresist made by Tokyo Ohka Co., Ltd. (TSMR8800) was formed by spin coating, a resist pattern was formed by ordinary photolithography, and oxygen plasma treatment was then performed to remove the exposed SAM film. The residual resist after the treatment was dissolved and removed with acetone, and the same contact angle evaluation was performed. As a result, the removed portion was 5 ° or less (completely wet), and the portion covered with the resist had a value of 92.4 °. It was confirmed that the SAM film was patterned.

  As another type of patterning, a resist pattern was previously formed with the same resist work, and after the same SAM film treatment, the resist was removed with acetone, and the contact angle was measured. The contact angle on the resist-covered platinum film was 5 ° or less (complete wetting), and that at other sites was 92.0 °, confirming that the SAM film was patterned. (See Figure 4)

  As another method, ultraviolet irradiation using a shadow mask was performed. The ultraviolet rays used were irradiated with vacuum ultraviolet light having a wavelength of 176 nm from an excimer lamp for 10 minutes. The contact angle of the irradiated portion was 5 ° or less (complete wetting), and that of the unirradiated portion was 92.2 °, confirming that the SAM film was patterned.

  Thereafter, a first patterned PZT precursor coating film is formed (E in FIG. 3), and heat treatment is performed according to a normal sol-gel process. The SAM film 2 disappears due to the high-temperature treatment such as the organic heat treatment temperature: 500 ° C. and the PZT crystallization temperature: 700 ° C. (F in FIG. 3).

The second and subsequent steps can be simplified for the following reasons (see D ′ to F ′ in FIG. 3).
Since the SAM film is not formed on the oxide thin film, the SAM film is formed only on the platinum film without (exposed) the PZT film by the first treatment.
Therefore, after the SAM treatment is performed on the first pattern-formed sample and the SAM film 2 is formed at a desired position (D ′ in FIG. 3), the PZT precursor liquid is separately applied (in FIG. 3). E ′) and heat treatment is performed (F ′ in FIG. 3).
By repeating this operation until a desired film thickness is obtained, PZT having a desired film thickness can be formed at a desired position. The patterning by this method can be suitably formed up to a ceramic film thickness of 5 μm.

Using this self-organization phenomenon is different from the conventional technology.
Conventional SAM film patterning and patterning of functional color materials (color filters, polymer organic EL, nanometal wiring) using the same have been completed with one SAM treatment and subsequent functional color material placement. 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. However, the process of forming the patterned SAM film by photolithography and etching is complicated each time.
Therefore, in the present invention, a thick film can be formed without a complicated process by combining an oxide thin film in which a SAM film is not particularly formed with a lower electrode capable of forming a SAM film (which is a constituent element of an electromechanical transducer). For the first time.

<Lower electrode 42 (substrate 1, first electrode)>
The material used for the lower electrode 42 is a metal that is heat resistant and forms a SAM film by reaction with alkanethiol. However, copper and silver form a SAM film, but cannot be used because they are altered by heat treatment at 500 ° C. or higher in the atmosphere. Furthermore, although gold satisfies both conditions, it cannot be used because it adversely affects the crystallization of the stacked PZT film.
Therefore, materials used for the lower electrode include platinum, rhodium, ruthenium, iridium, single metals, platinum-rhodium and other platinum group element alloy materials or platinum group element oxides. Alternatively, several kinds of laminated films are also effective.

<Upper electrode 44 (second electrode)>
The upper electrode 44 is formed of platinum or the like having a thickness of about 0.1 μm, for example. Unlike the lower electrode, the piezoelectric layer and the upper electrode are formed in an island shape independently for each piezoelectric element. Based on such a configuration, the piezoelectric elements are driven independently.

<Vibration plate 30>
The vibration plate 30 disposed on the silicon substrate may be several microns thick, and may be a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a film in which these films are stacked. 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 42 is electrically connected as a common electrode when a signal is input to the piezoelectric element, the diaphragm 30 under the lower electrode 42 is an insulator or a conductor and is used after being subjected to an insulation treatment.
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.

<Adhesion layer 41>
When the platinum group lower electrode 42 is disposed on these diaphragms 30, an adhesion layer 41 for increasing the film adhesion force is required. Possible materials for the adhesion layer 41 include titanium, tantalum, titanium oxide, tantalum oxide, titanium nitride, tantalum nitride, and laminated films thereof.

<Pressure chamber 21, pressure chamber substrate (Si substrate) 20>
The pressure chamber 21 communicates with the nozzle 11 and is partitioned by a pressure chamber substrate 20 (which constitutes a side surface), a nozzle plate 10 (which constitutes a lower surface), and a vibration plate 30 (which constitutes an upper surface). A laminated piezoelectric layer 43 for pressurizing the liquid in the pressure chamber 21 via the vibration plate 30 is provided.
The pressure chamber substrate 20 is composed of a silicon wafer or the like, and is formed by a conventional technique such as etching.

<Nozzle plate 10 and nozzle 11>
The nozzles 11 are formed in two rows on the nozzle plate 10 in a straight line. The nozzle plate 10 is formed by, for example, Ni electroforming, but is not limited thereto.

<Inkjet coating device>
FIG. 5 is a perspective view for explaining the ink jet coating apparatus. In FIG. 5, a Y-axis driving unit 201 is installed on a gantry 200, and a stage 203 on which a substrate 202 is mounted is installed on the platform 200 so as to be driven in the Y-axis direction. The stage 203 is accompanied by suction means such as vacuum and static electricity not shown, and the substrate 202 is fixed.
An X-axis drive unit 205 is attached to the X-axis support member 204, and a head base 206 mounted on the Z-axis drive unit 211 is attached to the X-axis support member 204, so that it can move in the X-axis direction. Yes. An ink jet head 208 that discharges ink is mounted on the head base 206. The ink jet head is supplied with ink from a colored resin ink supply pipe 210 from each ink tank (not shown).
Then, the ink ejected from the inkjet head 208 can be heated and crystallized using the laser head 212. Further, the laser head 212 is also used in the SAM film removal process. At this time, the desired shape and thickness of the functional thin film can be obtained by adjusting the discharge amount of the droplets of the electrode material or the precursor ink.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
In the above description, the well-known photolithographic etching method was introduced for patterning the SAM film. In this embodiment, the SAM film is removed by laser irradiation instead.
In order to uniformly remove the SAM film in the irradiation region, the beam profile of the laser light source is preferably a top hat. Further, in order to cut the light absorption rate of Pt and the carbon bond of the SAM film, the wavelength of the light source is preferably ultraviolet.

FIG. 6 shows the relationship between the laser power and the contact angle with respect to pure water when a YAG laser with a wavelength of 1064 nm is irradiated on a Pt substrate on which a SAM film is formed. It can be seen that when the power is gradually increased from 0%, the contact angle starts to decrease from around 20%, and the contact angle decreases almost linearly until the Pt substrate is damaged.
Among these, when the PZT precursor solution was applied to the region irradiated linearly at power of 40% and 30% by an ink jet method and dried, PZT on the substrate irradiated with power of 40% and 30% was obtained. The cross-sectional views are as shown in FIGS. 7 and 8, respectively. In the case of the power of 40% shown in FIG. 7, the contact angle becomes small due to the removal of the SAM film in the entire irradiation region, and coffee stain is generated. In the case of the power of 30% shown in FIG. 8, the SAM film partially remains and the contact angle is relatively large. As a result, the PZT film thickness is formed almost uniformly.

  As can be seen from the above results, when there is an optimum value at which coffee stain does not occur depending on the combination of the substrate and the ink, the coffee can be obtained by partially removing the SAM film by laser irradiation to obtain a desired contact angle. A functional film can be formed without stain.

  Here, in the present invention, a region in which only a part of the SAM film in the thickness direction is removed or a region in which the density of the SAM film is reduced in a planar manner so as to obtain a desired contact angle is a quasi-hydrophilic portion. Called. (On the other hand, a region where the SAM film is completely removed in the thickness direction of the SAM film and a region where the density of the SAM film is zero are referred to as a hydrophilic portion and are different from the quasi-hydrophilic portion.) Is formed in a desired shape to form a liquid repellent film removal site, the functional ink can be applied to a desired position, and a thin film having a desired pattern can be formed.

(Example 2)
In the first embodiment, partial removal of the SAM film was introduced using a laser. However, the SAM film was also partially removed by plasma, ultraviolet rays or a lamp (excimer lamp, low-pressure mercury lamp, etc.) using a mask or a photoresist. Removal (quasi-hydrophilic part formation) can be considered. Here, an example using oxygen plasma is shown.

  The step of patterning the photoresist on the Pt substrate on which the SAM film is formed has already been described. The processing effect of oxygen plasma mainly varies depending on (1) processing time, (2) RF POWER, (3) distance between electrodes, and (4) oxygen flow rate control factor. Here, the conditions of the processing time that can be handled most easily as a control factor were changed, and the effect was examined.

  The processing time conditions were 1 min, 3 min, and 5 min. The pure water contact angle measurement on the exposed SAM film after the oxygen plasma treatment was performed on the substrate that was subjected to the oxygen plasma treatment under each condition. This is shown in FIG. From this, it can be seen that the pure water contact angle on the SAM film decreases almost linearly in proportion to the oxygen plasma treatment time. Based on this, as in the case shown in Example 1, by adjusting the treatment time of oxygen plasma so as to obtain an optimum contact angle, a quasi-hydrophilic portion can be formed, and coffee stain is generated. And a functional film can be formed.

(Example 3)
A thermal oxide film (film thickness 1 micron) was formed on a silicon wafer, and a titanium film (film thickness 50 nm) was formed by sputtering as an adhesion layer. Subsequently, a platinum film (film thickness: 200 nm) was formed by sputtering as the lower electrode.

  Next, the SAM film is patterned by the method shown in the first and second embodiments, and PZT (53/47) is formed as a piezoelectric layer. 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). .

  This precursor solution was applied onto the patterned SAM film by the ink jet method using the ink jet apparatus of FIG. 5 (E in FIG. 3). 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. Crystallization was performed by irradiating the coating film with a laser, and a film indicated by F in FIG. 3 was obtained.

(Example of repeated processing)
By using the ink jet apparatus of FIG. 5 and the ink jet method, droplets were repeatedly ejected to the same place and laser irradiation was performed, so that overcoating could be performed.

(Example of thickening)
The previous step was repeated 15 times to obtain a 500 nm film. No defects such as cracks occurred in the film produced at this time.
Further, selective coating of the PZT precursor 15 times and subsequent laser irradiation were performed to perform crystallization treatment. Defects such as cracks did not occur in the film. The film thickness reached 1000 nm.

An upper electrode (platinum) was formed on this patterned film, and electrical characteristics and electromechanical conversion ability (piezoelectric constant) were evaluated.
The relative dielectric constant of the film is 1220, the dielectric loss is 0.02, the remanent polarization is 19.3 μC / cm ² , the coercive electric field is 36.5 kV / cm, and the characteristics are the same as those of a normal ceramic sintered body (P -E hysteresis curve is shown in FIG.

  The electromechanical conversion capacity was calculated from the amount of deformation caused by the application of an electric field with a laser Doppler vibrometer and fitting 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 liquid discharge head.

Example 4
As an electrode film, an oxide film such as platinum, SrRuO ₃ or LaNiO ₃ is dissolved in a solvent, applied by an ink jet method using the ink jet apparatus shown in FIG. it can. However, although alkanethiol has been used as a material for forming the SAM film, a silane coupling agent must be used when forming the SAM film on an oxide such as SiO ₂ .
From here on, as in the case of the piezoelectric body, the SAM film is patterned using photolithography, etching, laser, etc., and the electrodes are applied to the lyophilic portion by the ink jet method using the ink jet apparatus of FIG. Electrode films (lower electrode and upper electrode) were formed by repeating crystallization.

Furthermore, using the inkjet coating apparatus shown in FIG. 5, platinum was apply | coated only to the required part on a PZT film | membrane, and the upper electrode was formed. When coating, the coating area was defined using the contact angle contrast in the same manner as when the PZT precursor was coated. Since it is necessary to apply the upper electrode to a region smaller than the PZT film pattern in order to prevent a short circuit, it is necessary to provide a water repellent part also on the PZT film. Therefore, in this example, a resist was patterned and applied to a portion where platinum was not formed, and after drying the platinum at 120 ° C., the resist was peeled off and finally sintered at 250 ° C. The film thickness after firing was 0.5 microns, and the specific resistance was 5 × 10 ⁻⁶ ohm centimeters.

(Example 5)
FIG. 1 shows the configuration of a one-nozzle liquid discharge head. FIG. 11 shows the arrangement of a plurality of these. According to the present invention, the electromechanical transducer 40 shown in FIGS. 1 and 11 can be formed by a simple manufacturing process (and so as to have performance equivalent to that of bulk ceramics), and the back surface for subsequent pressure chamber formation. The liquid discharge head can be formed by removing the etching from the substrate and joining the nozzle plate having the nozzle holes.
In FIG. 1 and FIG. 11, descriptions of the liquid supply means, the flow path, and the fluid resistance are omitted.

(Example 6)
Next, an example of an ink jet recording apparatus equipped with the ink jet head (liquid discharge head) according to the present invention will be described with reference to FIGS. 12 is a perspective explanatory view of the ink jet recording apparatus, and FIG. 13 is a side explanatory view of a mechanism portion of the ink jet recording apparatus.

  The ink jet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 81, a recording head 94 including an ink jet head mounted on the carriage according to the present invention, an ink cartridge 95 for supplying ink to the recording head, and the like. A sheet feeding cassette (or a sheet feeding tray) 84 on which a large number of sheets 83 can be stacked from the front side is detachable in the lower portion of the apparatus main body 81. The manual feed tray 85 for manually feeding the paper 83 can be opened, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, and the printing mechanism section After a required image is recorded by 82, it is discharged to a discharge tray 86 mounted on the rear side.

  The printing mechanism 82 holds a carriage 93 slidably in the main scanning direction by a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), black (Bk) A head 94 comprising an ink jet head according to the present invention for ejecting ink droplets of each color has a plurality of ink ejection openings (nozzles) as the main scanning direction. They are arranged in the intersecting direction and mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 95 for supplying ink of each color to the 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 inkjet head is maintained at a slight negative pressure. Further, although the heads 94 of the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used.

  Here, the carriage 93 is slidably fitted to the main guide rod 91 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 92 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 100 is stretched between a driving pulley 98 and a driven pulley 99 that are rotationally driven by a main scanning motor 97, 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 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. A guide member 103, a transport roller 104 that reverses and transports the fed paper 83, a transport roller 105 that is pressed against the peripheral surface of the transport roller 104, and a leading end that defines a feed angle of the paper 83 from the transport roller 104 A 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. A roller 113 and a spur 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 onto the stopped sheet 83 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 83 has reached the recording area, the recording operation is terminated and the paper 83 is discharged.

  Further, a recovery device 117 for recovering defective ejection of the 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 head 94 is capped by the capping means, 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 head 94 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with the suction unit through the tube. Is removed by the cleaning means to recover the ejection failure. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since the inkjet head embodying the present invention is mounted in this inkjet recording apparatus, there is no ink droplet ejection failure due to vibration plate drive failure, stable ink droplet ejection characteristics are obtained, and image quality is improved. improves.

  As described above, according to the present invention, by controlling the contact angle with respect to the liquid, a thin film manufacturing method capable of forming a thin film so as to spread uniformly on the substrate while preventing coffee stain, and the thin film It has been found that an electromechanical conversion element including a thin film manufactured by the manufacturing method, a droplet discharge head including the electromechanical conversion element, and an ink jet recording apparatus can be provided.

1: Substrate 2: SAM film 3: Photoresist 4: Hydrophobic part 5: Hydrophilic part 10: Nozzle plate 11: Nozzle 20: Pressure chamber substrate 21: Pressure chamber 30 Diaphragm 40: Electromechanical transducer 41: Adhesion layer 42: Lower electrode 43: Electromechanical conversion film 44: Upper electrode 81: Apparatus body 82: Printing mechanism 82
83: paper 84: paper feed cassette 85: manual feed tray 86: paper discharge tray 91: main guide rod 92: sub guide rod 93: carriage 94: head 95: ink cartridge 97: main scanning motor 98: drive pulley 99: driven pulley 100: Timing belt 101: Paper feed roller 102: Friction pad 103: Guide member 104: Conveying roller 105: Conveying roller 106: Front roller 107: Sub-scanning motor 109: Printing receiving member 111: Conveying roller 112: Spur 113: Ejection Paper roller 114: spur 115, 116: guide member 117: recovery device 200: mount 201: Y-axis drive means 202: substrate 203: stage 204: X-axis support member 205: X-axis drive means 206: head base 208: inkjet head 210: Pipe for supply 212: Laser head

JP 2005-327920 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). Daniel Rhinow and Norert A Hampp, IEEE Transactions on nanobioscience 5, No. 3 (2006).

Claims (13)

A thin film manufacturing method for forming a thin film obtained by crystallizing functional ink on a substrate,
Forming a liquid repellent film on the substrate;
A liquid repellent film removing step of forming a liquid repellent film removal portion of a desired shape to be a semi-hydrophilic portion by removing a part of the liquid repellent film by any one selected from a laser light source, a lamp and plasma;
And a functional ink application step of applying the functional ink to the liquid-repellent film removal site on the substrate by a sol-gel method.   The thin film manufacturing method according to claim 1, wherein the laser light emitted from the laser light source has a top hat beam profile.   The thin film manufacturing method according to claim 1, wherein the laser light source and the lamp have an ultraviolet wavelength.   4. The thin film manufacturing method according to claim 1, wherein in the functional ink application step, the functional ink is ejected onto the substrate by an inkjet method and applied onto the substrate. The functional ink is an electrode material;
The thin film manufacturing method according to claim 4, wherein the functional ink application step obtains a desired shape and film thickness of the functional thin film by adjusting a discharge amount of the droplet. The functional ink is a ferroelectric precursor ink;
The thin film manufacturing method according to claim 4, wherein the functional ink application step obtains a desired shape and film thickness of the functional thin film by adjusting a discharge amount of the droplet.   7. The method according to claim 1, further comprising a functional ink heating and crystallization step in which the functional ink is heated and crystallized by a laser light source or a lamp to form a functional thin film having a desired shape. The thin film manufacturing method as described in any one of.   8. The thin film manufacturing method according to claim 7, wherein the laser light source or the lamp used in the functional ink heating / crystallization step is the same as the laser light source or the lamp used in the liquid repellent film removing step. An electromechanical conversion element comprising: a first electrode; a second electrode facing the first electrode; and an electromechanical conversion film sandwiched between the first electrode and the second electrode Because
The electromechanical conversion film is manufactured by the thin film manufacturing method according to any one of claims 1 to 8,
The electromechanical transducer according to claim 1, wherein the first electrode is a substrate according to claim 1.   The electromechanical transducer according to claim 9, wherein the second electrode is formed by an inkjet method. The electromechanical conversion film is made of a complex oxide of metal,
The said 1st electrode and the 2nd electrode are respectively comprised from the electrode which consists of a platinum group element or an oxide of a platinum group element, or these several types of laminated films, The Claim 9 or 10 characterized by the above-mentioned. The electromechanical transducer described.   A liquid discharge head comprising the electromechanical transducer according to claim 9.   An ink jet recording apparatus comprising the liquid discharge head according to claim 12.