JP5884272B2 - Thin film manufacturing method - Google Patents

Description

The present invention relates to an ink jet recording apparatus and a liquid discharge head used as an image forming apparatus (image recording apparatus) such as a printer, a facsimile machine, a copying apparatus, and an MFP (multifunction printer), as well as an electromechanical conversion element used therefor, The present invention relates to a thin film manufacturing apparatus and a thin film manufacturing method for manufacturing a thin film such as a mechanical conversion element.
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 And the ink droplets are ejected from the nozzles by pressurizing the ink in the pressurized chamber with the energy generated by the energy generating means.

Here, the piezoelectric element is formed by stacking 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 film such as a piezoelectric body are sandwiched therebetween.
As the piezoelectric body, lead zirconate titanate (PZT) ceramics or the like is used, and these are generally referred to as a metal composite oxide because they are mainly composed of a plurality of metal oxides.

  Conventional methods for forming individual piezoelectric elements include various vacuum film formation methods (for example, sputtering method, MO-CVD method (chemical vapor deposition method using a metal organic compound), vacuum deposition method, ion plate method on a lower electrode. Sol-gel method), sol-gel method, hydrothermal synthesis method, AD (aerosol deposition) method, coating / pyrolysis method (MOD), etc., followed by deposition, followed by photolithography after forming the upper electrode -The upper electrode is patterned by etching, and the piezoelectric film and the lower electrode are similarly patterned for individualization.

However, dry etching of metal composite oxides, particularly PZT, is not an easy work material. Si semiconductor devices can be easily etched by RIE (Reactive Ion Etching), but this type of material increases the plasma energy of ionic species, so special RIE using ICP plasma, ECR plasma, and helicon plasma is made. However, this increases the cost of the manufacturing apparatus. In addition, the selectivity with respect to the base electrode film cannot be obtained. In particular, the nonuniformity of the etching rate is fatal in a large area substrate.
If a hard-to-etch PZT film is disposed only in a desired portion in advance, the above-described processing step can be omitted, but the attempt has not been made except for a part.

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

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

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

Patent Document 1 describes a droplet discharge device that can efficiently irradiate a droplet including a discharged functional material with laser light and perform efficient drying and firing.
Patent Document 2 describes that in the sol-gel method, uniform piezoelectric characteristics can be obtained by irradiating far infrared rays to heat and crystallize the organometallic compound.
Furthermore, Patent Document 3 discloses a beam homogenizer that can form a rectangular beam spot on the irradiated surface with a uniform energy distribution in the long side direction without using an optical lens that requires high manufacturing accuracy. A laser irradiation device is described.

  However, even with the techniques according to Patent Documents 1 to 3, a patterned film having a desired film thickness cannot be easily manufactured.

  The present invention has been made in view of the above problems, and is an electromechanical conversion element including an electromechanical conversion film that is patterned and has a desired film thickness, a droplet discharge head including the electromechanical conversion element, and An object of the present invention is to provide an inkjet recording apparatus, and a thin film manufacturing apparatus and a thin film manufacturing method capable of easily manufacturing a patterned film having a desired film thickness.

In order to solve the above-described problems, an electromechanical transducer according to the present invention, a droplet discharge head and an ink jet recording apparatus including the electromechanical transducer, a thin film manufacturing apparatus, and a thin film manufacturing method are specifically described in the following (1 The technical features described in (3 ) to (3) .
(1): A thin film manufacturing method for forming a thin film in which a functional ink made of a metal complex oxide is crystallized on a substrate, and a liquid repellent film forming step for forming a liquid repellent film on the substrate; A liquid repellent film removing step of performing pulse irradiation with a rectangular spot-shaped laser beam to remove a part of the liquid repellent film to form a liquid repellent film removal portion having a desired shape; and the repellent film on the substrate. a functional ink imparting step of imparting a pre-Symbol functional ink Ri by the inkjet method liquid film removal site, by heating the functional ink by the laser beam of the spot shape used in the liquid-repellent film removing step A functional ink heating / crystallization step for crystallizing to form a functional thin film of a desired shape, and the shape of the laser beam used in the liquid repellent film removal step and the functional ink heating / crystallization step Is the shape of the functional thin film With the same shape or shape smaller than the same as a thin film manufacturing method characterized by forming the thin film by repeating the functional ink applying step and the functional ink heating and crystallization step.
(2): The liquid repellent film is hydrophobic, the substrate is hydrophilic, and the functional ink is not applied on the liquid repellent film, but only on the substrate. The method for producing a thin film as described in (1) above.
(3) The thin film manufacturing method according to (1) or (2), wherein the functional ink is a precursor ink, and the thin film is an electromechanical conversion film.

  According to the present invention, a patterned electromechanical conversion element including an electromechanical conversion film having a desired film thickness, a droplet discharge head and an inkjet recording apparatus including the electromechanical conversion element, and a patterned and desired pattern The thin film manufacturing apparatus and thin film manufacturing method which can manufacture the film | membrane which has a film thickness easily 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 schematic diagram which shows an inkjet coating apparatus. It is a schematic diagram which shows the heating of the PZT film | membrane using the laser light source in the thin film manufacturing process of this invention. It is the schematic of a laser light source with a rectangular spot shape. It is a schematic diagram of SAM patterning using a laser light source with a small spot shape. It is a figure showing the hysteresis curve of the PZT film | membrane obtained by this invention. It is a figure showing the contact angle on platinum. 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.

A thin film manufacturing apparatus according to the present invention is a thin film manufacturing apparatus for forming a thin film obtained by crystallizing functional ink on a substrate, and a liquid repellent film forming means for forming a liquid repellent film on the substrate; A liquid repellent film removing means for removing a part of the liquid repellent film with a laser beam to form a liquid repellent film removing portion having a desired shape, and the functionality of the liquid repellent film removing portion on the substrate by a sol-gel method. Functional ink applying means for applying ink; and functional ink heating / crystallization means for forming a functional thin film having a desired shape by heating and functionalizing the functional ink with a laser beam, and The liquid repellent film removing unit and the functional ink heating / crystallization unit are configured to irradiate a pulsed laser beam having a rectangular shape and the same shape as the functional thin film or smaller than the same shape. Features.
Next, a thin film manufacturing apparatus and a thin film manufacturing method according to the present invention, an electromechanical conversion element, a liquid droplet ejection head including the electromechanical conversion element, and an ink jet recording apparatus 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.
When the piezoelectric layer is PZT (refer to the technology relating to the formation of a thin film of metal composite oxide by the sol-gel method shown in Non-Patent Document 1: KD Budd, SK Dey, DA Payne, Proc. Brit. Ceram. Soc. 36, 107 (1985)), lead acetate, zirconium alkoxide and titanium alkoxide compounds are used 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 is obtained by a microcontact printing method using this phenomenon. See A. Kumar and GM Whitesides, Appl. Phys. Lett., 63, 2002 (1993), also shown in Non-Patent Document 3. See techniques used for processes such as pattern transfer and subsequent etching. 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).)

  Although the present invention is characterized in that the SAM film is removed by laser irradiation instead of the known photolithography etching, an example (conventional example) by the known photolithography etching will be described below. Details of removing the SAM film by irradiation will be described later in Examples. In the present invention, the PZT precursor is heat-treated by laser irradiation instead of performing the heat treatment of the PZT precursor according to the normal sol-gel process. (Conventional example) will be described, and details of performing heat treatment of the PZT precursor by laser irradiation 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).

  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 the thermal expansion difference 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. 4 is a perspective view for explaining the ink jet coating apparatus. In FIG. 4, 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.

Hereinafter, a process of removing the SAM film by laser irradiation and a process of heat-treating the PZT precursor by laser irradiation, which are features of the present invention, will be described.
Example 1
In the present invention, in patterning the SAM film, the SAM film is removed by laser irradiation instead of the known photolithography etching method.
FIG. 5 shows a process of patterning the SAM film (liquid repellent film) on the substrate with a laser light source. The rectangular spot shape can generally be formed through an aperture using an apparatus such as a fiber coupling or a laser stack. A schematic diagram thereof is shown in FIG. Furthermore, a beam profile of a top hat can be obtained using a beam homogenizer.

  By performing pulse irradiation on the substrate using this laser light source (liquid repellent film removing means), only the irradiated region is heated and the SAM film is removed (forms a liquid repellent film removal portion having a desired shape). Can do. The pulse irradiation described here represents a state in which light is irradiated while staying at a predetermined position for a certain time. Even if the spot moves slightly, if the moving distance x is x << w with respect to the width w of the spot shape, this is also pulse irradiation.

  In the example shown in FIG. 5, the hydrophilic portion has a rectangular shape with a width of 50 μm and a length of 1 mm arranged at equal intervals. If scanning is performed in the length direction using a laser light source with a small spot shape, it may not be a clean rectangle due to the accuracy of the laser or stage, but the end may become thick as shown in FIG. By using a (rectangular) spot-shaped laser, a desired SAM film pattern can be obtained.

  Further, depending on the material of the substrate to be irradiated, there is a concern about thermal diffusion. Therefore, by using a laser light source having a spot shape (smaller than the same shape) slightly smaller than the same shape as the desired SAM film pattern. The SAM film in a region slightly wider than the irradiation region is removed, and as a result, a desired pattern is obtained.

  After patterning the SAM film with a laser light source, a precursor solution of PZT is applied by an ink jet method using the ink jet apparatus shown in FIG. 4 (functional ink application means), and heated by a laser (functional ink heating). -Crystallization means). At this time, the shape and thickness of a desired functional thin film (film after heating and crystallization of the precursor solution) can be obtained by adjusting the discharge amount of the droplets.

  The region to which the PZT precursor solution is applied has the same shape as the spot shape of the laser light source. Therefore, only the portion coated with PZT can be uniformly heated by performing pulse irradiation using the laser light source used for removing the SAM film. Irradiation with a laser having a small spot shape causes a temperature distribution in the PZT film and causes cracks, but this problem is solved by using the same shape as the PZT film. In addition, since the SAM film is not irradiated, the PZT precursor can be applied by the ink jet method using the ink jet apparatus shown in FIG.

  Although not shown in the figure, a PZT precursor is applied to the entire surface of the substrate by spin coating, and a PZT film is formed by performing pulse irradiation using a similar laser light source. The same pattern as in the case of the ink jet method can be obtained by removing with the above.

(Example of repeated processing)
By using the ink jet apparatus of FIG. 4 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.

(Comparative Example 1)
A thermal oxide film (film thickness 1 μm) 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 (thickness: 200 nm) was formed by sputtering as the lower electrode.

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.
FIG. 9 shows a photograph of water contact angle measurement at the SAM film formation site and a water contact angle measurement photograph at the SAM film removal site.

  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.

  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.

  PZT (53/47) is formed as a piezoelectric layer. For 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 on the patterned SAM film by the ink jet method using the ink jet apparatus shown in FIG. 4 (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 2)
In Example 1 and Comparative Example 1, the ink jet method was used when forming the piezoelectric layer. However, an oxide such as platinum, SrRuO _3, or LaNiO ₃ was dissolved in a solvent as an electrode film, and ink jet was performed using the ink jet apparatus of FIG. The electrode film can be formed in the same manner as the piezoelectric layer by coating and laser irradiation. 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, 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. 4, 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 3)
FIG. 1 shows the configuration of a one-nozzle liquid discharge head. FIG. 10 shows the arrangement of a plurality of these. According to the present invention, the electromechanical transducer 40 shown in FIGS. 1 and 10 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. 10, descriptions of the liquid supply means, the flow path, and the fluid resistance are omitted.

Example 4
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. 11 is a perspective explanatory view of the ink jet recording apparatus, and FIG. 12 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, a lyophilic region equivalent to the spot shape can be obtained by irradiating a laser light source having an arbitrary spot shape with pulses.
In addition, in the functional thin film heating step, not the SAM film removal step, the spot shape of the laser light source has the same shape as the functional thin film, so that the functional thin film can be heated uniformly. A simple film can be formed. Further, since the SAM film is not heated, even if the functional thin film is heated, the SAM film is not removed and the functional ink can be applied continuously, so that the tact time can be greatly reduced. Furthermore, by irradiating the SAM film applied to the entire surface of the substrate, a region to which the functional ink is applied can be patterned in a later process, and a mask or a lamp is not necessary.
Also, a desired SAM film patterning can be achieved by using a laser light source having a top hat beam profile and the same spot shape as the target lyophilic region or a smaller spot shape in consideration of thermal diffusion. Therefore, it is preferable.
Furthermore, in addition to being able to adjust the amount of droplets by ejecting droplets by the inkjet method, it is possible to obtain a desired film thickness and patterning by adjusting the laser intensity and irradiation timing.
By disposing the second electrode, it can function as an electromechanical conversion element, and cost reduction can be obtained by performing this by an ink jet method. Furthermore, the performance as an electromechanical conversion element can be improved by using a more preferable material.

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 conversion element, 41: Adhesion layer, 42: Lower electrode, 43: Electromechanical conversion film, 44: Upper electrode,
81: apparatus main 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: Feed roller, 102: Friction pad, 103: Guide member 104: Transport roller, 105: Transport roller, 106: tip roller, 107: sub-scanning motor 109: printing receiving member, 111: transport roller, 112: spur, 113: paper discharge 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

Japanese Patent No. 4232753 Japanese Patent No. 3838342 JP 2005-1229889 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 AHampp, IEEE Transactions on nanobioscience 5, No. 3 (2006).

Claims (3)

A thin film manufacturing method for forming a thin film in which a functional ink made of a metal complex oxide is crystallized on a substrate,
Forming a liquid repellent film on the substrate;
A liquid repellent film removing step of performing pulse irradiation with a rectangular spot-shaped laser beam and removing a part of the liquid repellent film to form a liquid repellent film removal portion of a desired shape;
A functional ink imparting step of imparting a pre-Symbol functional ink Ri by the ink jet method on the liquid repellent film removal site in the substrate,
A functional ink heating and crystallization step in which the functional ink is heated and crystallized by the spot-shaped laser beam used in the liquid repellent film removing step to form a functional thin film having a desired shape; Prepared,
The shape of the laser beam used in the liquid repellent film removal step and the functional ink heating / crystallization step is the same shape as the functional thin film or a shape smaller than the same,
A thin film manufacturing method comprising forming the thin film by repeating the functional ink application step and the functional ink heating / crystallization step. The liquid repellent film is hydrophobic,
The substrate is hydrophilic;
The thin film manufacturing method according to claim 1, wherein the functional ink is not applied on the liquid-repellent film but only on the substrate. The functional ink is a precursor ink,
The thin film manufacturing method according to claim 1, wherein the thin film is an electromechanical conversion film.